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CONCRETE MIX DESIGN M30 GRADE IS-10262-2009

noreply@blogger.com (Rizwan Ahmad) — Thu, 12 Oct 2017 17:39:00 +0000

Concrete mix design is required to obtained target strength in building and structures. Concrete Mix design of M30 grade of concrete can be find from the example given below.

1.Design Stipulation For Proportioning

Grade Designation = M-30

Type of cement = OPC 53 grade confirming to IS-12269-1987

Exposure condition = Normal (for reinforced concrete)

Method of placing = Pumping

Degree of supervision = Good

Maximum nominal size of aggregate = 20 mm

Maximum Cement content =540 kg/m³

Minimum Cement content = 310 kg/m³

Maximum water cement ratio = 0.45

Workability = 50-75 mm (Slump)

Type of aggregate = Crushed angular aggregate

Chemical admixture type = Superplasticiser

2. Test Data For Material

Cement used = Coromandal King OPC 53 grade

Sp. Gravity Cement = 3.15

Sp. Gravity Fine Aggregate = 2.61

Sp. Gravity Coarse Aggregate (20mm) = 2.88

Sp. Gravity Coarse Aggregate (10mm) = 2.868

Chemical admixture = Superplasticiser confirming IS 9103

Water absorption of coarser aggregate(20mm) = 0.97%

Water absorption of coarser aggregate(10mm) = 0.87%

Free surface moisture = Nil

Sp. Gravity of Combined Coarse Aggregates = 2.882

3. Target Mean Strength

Himsworth constant for 5% risk factor is 1.65. In this case standard deviation is taken from IS:456 against M 30 is 4.0.

f_target = f_ck + 1.65 x S

Target Mean Strength = 42 Mpa

Where,

S = standard deviation in N/mm²= 4 (as per table -1 of IS 10262- 2009)

4. Selection of water cement ratio

Maximum Water Cement Ratio = 0.45

Adopted Water Cement Ratio = 0.42

5. Selection Of Water Content

Maximum Water content (10262-table-2) = 186 ltr

Estimated Water content for 50-75 mm Slump = 160 ltr

Superplasticiser used = 0.5 % by wt. of cement

6. Cement Content Calculation

Water Cement Ratio = 0.42

Cement Content (160/0.42) = 380 kg/m³

Corrected water content = 160 ltr

Cement content =

From Table 5 of IS 456,

Minimum cement Content for mild exposure condition

= 310 kg/m³

380 kg/m³ > 300 kg/m³, hence, OK.

This value is to be checked for durability requirement from IS: 456.

In the present example against mild exposure and for the case of reinforced concrete the minimum cement content is 310 kg/m³ which is less than 380 kg/m³. Hence cement content adopted = 380 kg/m³.

As per clause 8.2.4.2 of IS : 456

Maximum cement content = 540 kg/ m3

7. Calculation of sand and coarse aggregate

From Table 3 of IS 10262- 2009,

For Nominal maximum size of aggregate = 20 mm,

Zone of fine aggregate = Zone II

And For w/c = 0.42

Vol. of C.A. as per table 3 of IS 10262 = 62%

Adopted Vol. of Coarse Aggregate = 62%

Adopted Vol. of Fine Aggregate ( 1-0.62) = 38%

8. Estimation of the mix ingredients

Volume of Concrete in m^{3 = 1.0}

Volume of cement in m3 = 0.12

(Mass of Cement) / (Sp. Gravity of Cement)x1000

Volume of water in m3 = 0.160

^{(Mass of Water) / (Sp. Gravity of Water)x1000}

^{Volume of Admixture 0.5% in m}^{3 = 0.00160}

^{(Mass of Admixture)/(Sp. Gravity of Admixture)x1000}

^{Volume of All in Aggregate in m}^{3 = 0.718}

^{Serial. number. 1 – (Sr. no. 2+3+4)}

^{Volume of Coarse Aggregate in m}^{3 = 0.445}

^{Serial. number. 5 x 0.62}

^{Volume of Fine Aggregate in m}^{3 = 0.273}

^{Serial. number. 5 x 0.38}

^{Mix Proportions
for One Cum of Concrete}

^{Mass of Cement in kg/m}^{3 = 380}

^{Mass of Water in kg/m}^{3 = 160}

^{Mass of Fine Aggregate in
kg/m}^{3 = 711}

^{Mass of Coarse Aggregate in
kg/m}^{3 = 1283}

^{Mass of 20 mm in kg/m}^{3 = 924}

^{Mass of 10 mm in kg/m}^{3 = 359}

^{Mass of Admixture in kg/m}^{3 =}^1.9

^{Water Cement Ratio =}^0.42

CONCRETE MIX DESIGN M40 GRADE

noreply@blogger.com (Rizwan Ahmad) — Mon, 09 Oct 2017 11:57:00 +0000

WHAT IS CONCRTE MIX DESIGN ?

The process of selecting suitable ingredients of concrete and determining their relative amounts with the objective of producing a concrete of the required, strength, durability, and workability as economically as possible, is termed the concrete mix design.

POINT TO BE REMEMBER WHILE MAKING MIX DESIGN

The grade designation giving the characteristics strength required of concrete.

The type of cement influences the rate of development of compressive strength of concrete.

Maximum nominal size of aggregate to be used in concrete may be as large as possible within the limits prescribed by the IS : 456-2000.

The cement content is to be limited from shrinkage, crack, and creep.

The workability of concrete for satisfactory placing and compacting is related to the size and shape of the section,quantity and spacing of reinforcement and technique used for transportation, placing and compaction.

CONCRETE MIX DESIGN-M40 GARDE EXAMPLE

1.Design Stipulation For Proportioning

Grade Designation = M-40

Type of cement = O.P.C-43 grade confarming to IS 8112

Maximum nominal size of aggregate = 20 mm

Maximum Cement content =450 kg / m³

Minimum Cement content = 320 kg / m³

Maximum water cement ratio = 0.45

Workability = 100 mm (slump)

Exposure condition = Severe (for reinforced concrete)

Method of placing = Pumping

Degree of supervision = Good

Type of aggregate = Crushed angular aggregate

Chemical admixture type = Superplasticiser

2. Test Data For Material

Cement used = OPC 43 grade confirming IS 8112

Sp. Gravity Cement = 3.15

Sp. Gravity Fine Aggregate = 2.61

Sp. Gravity Coarse Aggregate (20mm) = 2.65

Sp. Gravity Coarse Aggregate (10mm) = 2.66

Chemical admixture = Superplasticiser confirming IS 9103

Water absorption of coarser aggregate = 0.5%

Water absorption of coarser aggregate = 1%

Free surface moisture = Nil

3. Target Mean Strength

Target Mean Strength = 40 + ( 5 X 1.65 ) = 48.25 Mpa

Selection of water cement ratio

Assume water cement ratio = .40 - 0.45

4. Selection Of Water Content

Approximate water content for 20mm max. Size of aggregate = 180 kg /m³ (As per Table No. 2 , IS : 10262 ). As plasticizer is proposed we can reduce water content by 20%.

Now water content = 180 X 0.8 = 140kg /m³

5. Cement Content Calculation

Water cement ratio = 0.40

Water content per m³ of concrete = 144 kg

Cement content = 144/0.35 = 411.4 kg / m³

Say cement content = 412 kg / m³ (As per contract

Minimum cement content 350 kg / m³ )

Hence O.K.

6. Calculation of sand and coarse aggregate

V = [ W + (C/S_c) + (1/p) . (f_a/S_fa) ] x (1/1000)

V = [ W + (C/S_c) + {1/(1-p)} . (ca/S_ca) ] x (1/1000)

Where

V = absolute volume of fresh concrete, which is equal to gross volume (m³) minus the volume of entrapped air ,

W = mass of water ( kg ) per m³ of concrete ,

C = mass of cement ( kg ) per m³ of concrete ,

S_c = specific gravity of cement,

(p) = Ratio of fine aggregate to total aggregate by absolute volume ,

(fa) , (ca) = total mass of fine aggregate and coarse aggregate (kg) per m³ of
Concrete respectively, and

Sfa , Sca = specific gravities of saturated surface dry fine aggregate and Coarse aggregate respectively.

As per Table No. 3 , IS-10262, for 20mm maximum size entrapped air is 2% .

Assume F.A. by % of volume of total aggregate = 36.5 %

0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.365 ) ( Fa / 2.61 )] ( 1 /1000 )

=> Fa = 660.2 kg

Say Fa = 660 kg.

0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.635 ) ( Ca / 2.655 )] ( 1 /1000 )

=> Ca = 1168.37 kg.

Say Ca = 1168 kg.

Considering 20 mm : 10mm = 0.6 : 0.4

20mm = 701 kg .
10mm = 467 kg .

Hence Mix details per m³

Cement = 400 kg
Water = 160 kg
Fine aggregate = 660 kg
Coarse aggregate 20 mm = 701 kg
Coarse aggregate 10 mm = 467 kg
Admixture = 0.6 % by weight of cement = 2.4 kg.
Recron 3S = 900 gm

Water: cement: F.A.: C.A. = 0.4: 1: 1.65: 2.92

7. Observation for concrete mix design

% Strength of concrete : The strength of concrete increases with

age.

Table for strength of concrete at various age

Age	Strength per cent
1 day	16%
3 days	40%
7 days	65%
14 days	90%
28 days	99%

A. Mix was cohesive and homogeneous.

B. Slump value = 120 mm

C. No. of cube casted = 9

7 days average compressive strength = 42.07 N/mm2

28 days average compressive strength = 52.52 N/mm2

which is greater than 48.25 N/mm2

Hence the mix accepted.

DIFFERENT METHOD OF MIX DESIGN OF CONCRETE PROCEDURE

noreply@blogger.com (Rizwan Ahmad) — Sun, 01 Oct 2017 20:35:00 +0000

MIX DESIGN

The procedure of selecting suitable ingredients and determine their relative proportions with the objectives of producing concrete of having certain minimum workability, strength and durability as economically as possible is known as mix design.

The various factors to be consider in specifying a concrete mix are :

Water cement ratio

Cement content gradation

Consistency of the fresh concrete

METHOD OF MIX DESIGN OF CONCRETE

Trial and error method
American concrete institute method.
Maximum density of aggregate method
Surface area of aggregate method
Fineness modulus method
Void cement ratio and mortar void ratio method
Road note method

TRIAL AND ERROR METHOD

Based on the relationship between the w/c ratio and compressive strength. the design of the mix can be made by following steps :

Select the water cement ratio to suit the requirement of the strength and durability.

With this water cement ratio prepare trial batches with different aggregate cement ratios. From this it is possible to determine the optimum proportion and amount of the aggregate that will produce a workable mix with a minimum of the pastes content for determining the fine aggregate. It can be said that in the correct amount of sand is the minimum which will produce enough mortar to fill the spaces between the coarse aggregate and slightly more for workability. Understanding creates hardness and over standing results in less yield. with judgement and experience one ma arrive at the proportions of fine and coarse aggregate.

Having fixed water cement ratio, aggregate cement ratio and the amount of fine aggregate in the total aggregate content, block of concrete can be prepared in the laboratory following the standard procedure. After the required period of curing the blocks can be tested for its compressive strength.

mix can be slightly adjusted, if necessary, by changing the w/c ratio or the aggregate cement ratio suit the actual requirement of the job.

In the trial and error method, due consideration has to be given for the moisture content of the aggregates.

AMERICAN CONCRETE INSTITUTE METHOD (ACI METHOD)

This is the common method for design of concrete mix. the following are the steps :

Select the water cement ratio to concrete of the required durability and strength. if water cement ratio is determine by both methods and then the lower of the two values obtained should be used.

Select the lowest slump from ASI table.

The maximum size of aggregate recommended for the types of construction is selected by ASI table. Within the limit shown, the larges permissible maximum size should be employed, except as dictated by available and economy.

Estimate from the test data, minimum proportion of fine to coarse aggregate and the lowest water content as that will give the required degree of workability.

The cement content is computed by dividing the total water content by the w/c ratio.

The bulk volume of the dry rodded coarse aggregate per unit volume of concrete for the particular maximum size of the aggregate and fineness modulus of the sand is determine.

Determine the trial mix proportions and make adjustment if necessary for the materials and water cement ratio.

MAXIMUM DENSITY OF AGGREGATE METHOD

It is also known as fullar and thomson method of concrete mix design, the basis for proportioning the aggregate is maximum density. For this method, the studies made by fullar and thomson, in which sieve analyses were made to obtain proportions aggregate giving maximum density of concrete, were used. But this method is not in much uses now.

Maximum density of this combined aggregate can be determine is follow. In a of known volume certain proportions of any rodded mixed aggregate are filled in. Sand is taken as 0, 20, 30, 40, 50, 60 and 100% of the total weight. After each filling of the mould with the combined aggregates, weight is taken. A curve is then drawn showing the percentage of sand in the aggregate by weight v/s unit weight of the total aggregate in the mould, from this percentage of sand at which unit weight is maximum can be determined.

TYPES OF LOAD ACTING ON BUILDING (IS : 875)

noreply@blogger.com (Rizwan Ahmad) — Sun, 24 Sep 2017 17:48:00 +0000

The loads acting on structures can be broadly classified as vertical loads, horizontal loads and longitudinal loads.

The Vertical Loads Consist Of :

1. Dead load : It is the self weight of structure which are transferred to structure throughout the life span. It majorly consists of the weight of walls, columns, beams, roofs etc.

Dead Load = volume of each section x unit weight of material

Sl. No	Material	Unit Weight Of Material
1	Plain Cement Concrete	18.8 kN/m³
2	Reinforced Cement Concrete	24 kN/m³
3	Brick Masonry	18.8 kN/m³
4	Timber	5-8 kN/m³
5	Stone Masonry	20.4-26.5 kN/m³

2. Live load : Live loads are either movable or moving load on building. It includes weights of movable partitions or furniture etc. The minimum value of live loads to be assumed are specified by the IS 875 (part 2)–1987.

Live Load For The Following Occupancies :

Educational buildings

Assembly building

Institutional buildings

Mercantile buildings

Industrial buildings

Business and office buildings

Storage rooms

Residential buildings–dwelling houses, hotels, hostels, boiler rooms and plant rooms, garages.

Imposed Or Live Load for different Occupancies :

IMPOSED OR LIVE LOAD ON STRUCTURE

However, reductions in assumed total live loads on floors may be made in designing columns, walls, their supports and foundations as shown in table below.

Number of floors carried by member under consideration	Reduction of total live load on all floors above the member under consideration %
1	0
2	10
3	20
4	30
5-10	40
Over 10	50

3. Snow load : Load caused by the snowfall on the roof of the building. It is consider as vertical load acting on a building.

According to the IS 875 (part 4) – 1987, the minimum snow load on a roof area is obtained by the expression

Where

S = Design snow load on plan area of roof.

= Shape coefficient

S₀ = Ground snow load.

The Horizontal Loads Consist Of :

1. Wind load : It is the horizontal load caused by the blowing wind. Wind load is required to be considered in structural design especially when the height of the building exceeds two times the dimensions latreal to the exposed wind surface.

The calculation of wind loads depends on the two factors :

Velocity Of Wind
Size Of The Building

According to the IS-875 (Part 3) -1987) wind load calculating by the following expression :

V_z = k_1.k₂.k_3.V_b

Where k₁ = Risk coefficient
k₃ = Topography factor
k₂ = Coefficient based on terrain, height and structure size.
V_b= basic wind pressure is shown in a map of India.

The design wind pressure is given by :

p_z = 0.6 V²_z

where

p_z is in N/m² at height Z

V_z is in m/sec.

Note : wind pressure act uniformly up to the height of 30 meter, Above 30 m height, the wind pressure increases.

2. Earthquake load : It is the vibrational load on structure caused by the earthquake. This vibration occur in all three direction, but the movement in vertical direction do not cause forces in superstructure to any significant extent. But the horizontal movement of the building at the time of earthquake is to be considered while designing.

For monolithic reinforced concrete structures located in the seismic zone 2, and 3 without more than 5 stories high and importance factor less than 1, the seismic forces are not critical.

HOW TO PERFORM COMPRESSIVE STRENGTH TEST OF CEMENT(IS:4031-PART 6-1988) ?

noreply@blogger.com (Rizwan Ahmad) — Tue, 12 Sep 2017 19:04:00 +0000

Compressive strength of cement is determined by performing the compressive strength test on mortar cubes compacted by vibration machine. For the preparation of cement mortar, Standard sand (IS:650) is used. The specimen is prepared in the form of cubes 70.6 mm x 70.6 mm x 70.6 mm.

OBJECTIVE

To determine the compressive strength of mortar cubes (standard).

APPARATUS

Cubic Mould : The capacity of cubic mould is 70.6 x 70.6 x 70.6 mm3 (IS : 10080).

Vibration Machine : The vibration machine should be works as per the IS : 10080.

Balance : The balance measuring weigh 1000 g with an accuracy of 1 g.

Measuring Cylinder : The capacity of measuring cylinder s 200 ml with an accuracy of 1 mm.

Enamel tray, Trowel, Poking rod other apparatus required.

PROCEDURE

The test specimens are 70.6 mm cubes having face area of about 5000 sq. mm. Large size specimen cubes cannot be made since cement shrinks and cracks may develop.

The temperature of water and test room should be 27°± 2°C.

A mixture of cement and standard sand in the proportion 1:3 by weight is mixed dry with a trowel for one minute and then with water until the mixture is of uniform colour.

Three specimen cubes are prepared. The material for each cube is mixed separately.

The quantities of cement, standard sand and water are 185 g, 555 g and (P/4) + 3.5, respectively where P = percentage of water required to produce a paste of standard consistency.

The mould is filled completely with the cement paste and is placed on the vibration table. Vibrations are imparted for about 2 minutes at a speed of 12000±400 per minute.

The cubes are then removed from the moulds and submerged in clean fresh water and are taken out just prior to testing in a compression testing machine.

Compressive strength is taken to be the average of the results of the three cubes.

The load is applied starting from zero at a rate of 35 N/sq mm/minute. The compressive strength is calculated from the crushing load divided by the average area over which the load is applied.The result is expressed in N/mm2.

CALCULATION

P = Maximum load applied to the cube.

A=Cross sectional area (Calculated from the mean dimensions).

Compressive strength is reported to the nearest 0.5 N/mm². when wrong specimen have prepared, or that give strengths differing by more than 10% from the average value of all the test specimen should not be considered.

STANDARD SPECIFICATION

CEMENT TYPE	COMPRESSIVE STRENGTH (Mpa)
CEMENT TYPE	1 Day	3 Days	7 Days	28 Days
OPC(33)	not specified	16	22	33
OPC(43)	not specified	23	33	43
OPC(53)	not specified	27	27	53
SRC	not specified	10	16	33
PPC	not specified	16	22	33
RHPC	16	27	—	—
PSC	not specified	16	22	33
High alumina	30	35	—	—
Super sulphated	not specified	15	22	30
Low heat	not specified	10	16	35

HOW TO CHECK SOUNDNESS OF CEMENT BY LEE-CHATELIERS MATHOD (IS:4031-(PART 3)-1988) ?

noreply@blogger.com (Rizwan Ahmad) — Tue, 12 Sep 2017 17:40:00 +0000

In the soundness test a specimen of hardened cement paste is boiled for a fixed time so that any tendency to expand is speeded up and can be detected. Soundness means the ability to resist volume expansion.

OBJECTIVE

To determine the soundness of hardened cement paste by le-Chateliers method.

APPARATUS

Le-Chateliers Apparatus : The size of apparatus should be made as per IS: 5514.

Water Bath : The water bath should have a minimum temperature 100 with an accuracy of 1.

Caliper : The measuring length of caliper is 30 cm with 0.5 mm accuracy.

Measuring Cylinder : The volume of measuring cylinder is 100 ml with an accuracy of 1 ml.

Balance : The should weigh 100 g accurately with an accuracy of 1 g.

Glass sheets (2 nos), Enamel tray, trowel are the other apparatus required for test.

PROCEDURE

The mould is placed on a glass sheet and is filled with neat cement paste formed by gauging 100 g cement with 0.78 times the water required to give a paste of standard consistency.

The mould is covered with a glass sheet and a small weight is placed on the covering glass sheet.

The mould is then submerged in the water at temperature of 27°-32°C.

After 24 hours, the mould is taken out and the distance separating the indicator points is measured to the nearest 0.5 mm (L1).

The mould is again submerged in water. The water is now boiled for 3 hours.

The mould is removed from water and is cooled down.

The distance between the indicator points is measured again to the nearest of 0.5 mm (L2).

The difference between the two measurements represents the unsoundness of cement.

CALCULATION

The difference between the two measurements to the nearest of 0.5 mm represents the unsoundness of cement.

Soundness Of Cement = L₁-L₂

PRECAUTIONS

All the measurements should be done accurately.

Extra pressure should not apply while filling the moulds.

During boiling water level should not fall below the height of the mould.

STANDARD SPECIFICATIONS

Type/Name of cement	Reference Indian standard	Expansion (max.)
OPC (33)	IS:269-1989	10 mm
OPC (43)	IS:8112-1989	10 mm
OPC (53)	IS:12269-1987	10 mm
Rapid hardening	IS:8041-1990	10 mm
Low heat cement	IS:12600-1989	10 mm
Super sulphated	IS:6909-1990	5 mm
Portland pozzolana	IS:1489-1991(part 1)	10 mm
PSC	IS:455-1976	10 mm
High alumina cement	IS:6452-1989	5 mm
SRC	IS:12330-1988	10 mm
Masonry cement	IS:3466-1988	10 mm
IRS-T-40	Railway standards	5 mm

GENERAL GUIDLINES FOR REINFORCEMENT BAR

noreply@blogger.com (Rizwan Ahmad) — Tue, 12 Sep 2017 10:09:00 +0000

REINFORCEMENT BAR DETAIL GUIDELINE

The material added to concrete for resist the tension produce within the internal fibres of structure during loading is called steel bars or reinforcement bars. These bar installed in the tension zone to strengthen the structure and avoid to produces cracks during loading. when the bars is also use in compression zone the strength increases up to 20%, if deformed bars is used then strength will increase up to 40%.

TYPES OF REINFORCEMENT

1. Mild Steel Plain Bars : A mild steel bar made up of with out surface deformation is called mild steel plain bar.

IS: 432 (part 1) Specification :

In this categories, for bar up to 20 mm diameter, characteristic yield strength is 250 N/mm2.

For bar over 20 mm diameter, characteristic yield strength is 240 N/mm2.

In tension, bar up to 20 mm diameter, the permissible stresses 140 N/mm2 in steel reinforcement is taken into account and for over 20 mm diameter, permissible stresses 130 N/mm2 is taken into account

Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account.

Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses 140 N/mm2 in the steel reinforcement is consider for bar diameter up to 20 mm, permissible stresses 130 N/mm2 for bar diameter over 20 mm is consider.

2. Mild Steel Hot Rolled Deformed Bars : A mild steel bar made up of surface deformation is called mild steel deformed bar.

IS: 1139 Specification :

In this categories, for bar up to 20 mm diameter, characteristic yield strength is 250 N/mm2.

For bar over 20 mm diameter, characteristic yield strength is 240 N/mm2.

In tension, bar up to 20 mm diameter, the permissible stresses 140 N/mm2 in steel reinforcement is taken into account and for over 20 mm diameter, permissible stresses 130 N/mm2 is taken into account

Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account.

Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses 140 N/mm2 in the steel reinforcement is consider for bar diameter up to 20 mm, permissible stresses 130 N/mm2 for bar diameter over 20 mm is consider.

3. Medium Tensile Steel Plain Bars : This type of bars shows a medium characteristic yield strength.

IS: 432 (part 1) Specification :

In this categories, for bar up to 20 mm diameter, characteristic yield strength is 350 N/mm2.

For bar between 20 mm to 40 mm diameter, characteristic yield strength is 340 N/mm2.

In tension, bar for any diameter, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2

Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account for any diameter.

Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2.

4. Medium Tensile Steel Deformed Bars :

IS: 432 (part 1) Specification :

In this categories, for bar up to 20 mm diameter, characteristic yield strength is 350 N/mm2.

For bar between 20 mm to 40 mm diameter, characteristic yield strength is 340 N/mm2.

For bar over 40 mm diameter, characteristic yield strength is 320 N/mm2
In tension, bar for any diameter, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2

Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 130 N/mm2 in steel reinforcement is taken into account for any diameter.

Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses is half the guaranteed yield stress subjected to a maximum of 190 N/mm2.

5. High Yield Strength Steel Deformed Bars : HYSD is the high yield strength deformed bars have ribs on the surface and this increases the bond strength at least by 40%.

IS: 1139 Specification :

In this categories, bar for all size diameter, characteristic yield strength is 415 N/mm2.

In tension, bar up to 20 mm diameter, the permissible stresses 230 N/mm2 in steel reinforcement is taken into account and for over 20 mm diameter, permissible stresses 230 N/mm2 is taken into account

Compression in column bar, compression in bars in a beam or slab when compressive resistance of concrete is taken into account, the permissible stresses 190 N/mm2 in steel reinforcement is taken into account.

Compression in bars in a beam or slab when the compressive resistance of the concrete is taken into account, the permissible stresses 190 N/mm2 in the steel reinforcement is consider for bar diameter up to 20 mm, permissible stresses 190 N/mm2 for bar over 20 mm diameter is consider.

INITIAL AND FINAL SETTING TIME OF CEMENT TEST (IS: 4031-(PART-5)-1988)

noreply@blogger.com (Rizwan Ahmad) — Thu, 07 Sep 2017 19:26:00 +0000

INITIAL AND FINAL SETTING TIME CEMENT TEST

The initial setting time may be defined as the time taken by the paste to stiffen or solidify to such an extent that the Vicat’s needle is not permitted to move down through the paste to within 5 to 7 mm measured from the bottom of the mould.

The final setting time is the time after which the paste becomes so hard that the angular attachment to the needle, under standard weight, fails to leave any mark on the hardened concrete.

Factors Affecting Initial And Final Setting Time Of Cement :

The factors influencing the setting properties of cement are :

Its composition, The effect of gypsum is to increase the setting time of freshly ground cement.

The percentage of retardant.

Degree of calcination.

Fineness of grinding.

Aeration subsequent to grinding clinker.

Percentage of water used to make cement paste.

The temperature of the mixing water.

Cement and the atmosphere where the cement paste is placed.

OBJECTIVE

To determine the initial and final setting time of cement paste of normal consistency.

APPARATUS

Vicat’s Apparatus :

SAMPLE/SPECIMEN

300 gm of cement is taken and then mix it with the required water percentage mentioned in the consistency test of cement.

PROCEDURE FOR INITIAL SETTING TIME

The prepared cement paste is filled in the vicat mould.

The square needle of cross-section 1 mm x 1 mm is attached to the movable rod of the Vicat apparatus.

Then the needle is allowed to quickly release to penetrate in the cement paste. during initial stage, the needle penetrates completely. It is then taken out and dropped at a fresh place. The test procedure is repeated at regular intervals till the needle does not penetrate completely. The needle should penetrate upto about 5 mm measured from bottom.

The initial setting time is found out by taking the interval between the addition of water to cement and the stage when needle stops to penetrate completely. The time should be less than 30 minutes for ordinary cement.

PROCEDURE FOR FINAL SETTING TIME :

300 gm of cement is taken and then mix it with the required water percentage mentioned in the consistency test of cement.

The prepared cement paste is then fill in the vicat mould.

Instead of square needle, annular collar is used. The annular collar is attached to the movable rod of vicat apparatus.

The annular rod is gently released. The time at which the annular rod makes an impression on test block and the collar fails to do so is noted.

The final setting time is found out by taking the difference between the time at which water is added to cement and time as recorded in.

The final setting time for ordinary cement should be 10 hours.

Initial And Final Setting Time Of Various Types Of Cement :

Ordinary Portland Cement : The initial setting time of OPC should not be less than 30 minutes and the final setting time of this type of cement should not be greater than 10 hours or 600 minutes.

Rapid Hardening Cement : for this type of cement, initial and final setting time is same as OPC cement.

Portland Pozzolana Cement : For this type of cement, initial and final setting time is same as OPC cement.

Low Heat Portland Cement : For this type of cement, initial and final setting time is not less than 30 min and not greater than 600 minutes.

Portland Blast Furnace Slag Cement : For this type of cement, initial and final setting time is same as OPC cement.

FINENESS TEST OF CEMENT (IS:4031-1996)

noreply@blogger.com (Rizwan Ahmad) — Thu, 07 Sep 2017 10:10:00 +0000

Test for fineness of cement is carried out for proper grinding of cement and to measure the mean size of the grains in it.

METHOD OF TESTING FINENESS OF CEMENT :

Sieve Analysis Method

Weighing a 100 g of cement with accuracy of 0.1 g as a sample and if any air-set lumps present in the sample are broken with finger. The sample is placed on a 90 micron sieve and continuously sieved for 15 minutes.

The residue should not exceed the following limits :

For Ordinary Portland Cement : The residue present in OPC cement should not exceed 10% by the dry weight of cement. The specific surface of this type of cement should not be less than 225 m2/kg.
For Rapid Hardening Cement : The residue present in this rapid hardening cement should not exceed 5% by the dry weight of cement. The specific surface of this type of cement should not be less than 325 m2/kg.
For Portland Puzzolana Cement : The residue present in PPC cement should not exceed 5% by the dry weight of cement. The specific surface of this type of cement should not be less than 300 m2/kg.

Test Procedure

Objective

To determine the fineness of cement by dry sieve method.

Apparatus

Standard BIS Sieve No. 9 : With capacity of retaining particle size over 90 micron.

Weighing Balance : Measures 10 g of cement with accuracy 0.01 mg.
Glass rod, Stoppered Jar Pen, Lid other apparatus used.

Sample/Specimen

100 g of cement sample is taken and broken air-set lumps in the sample with fingers.

Procedure

Weigh approximately 10 g of cement to the nearest 0.01 g and place it on the sieve.
Agitate the sieve by swirling, planetary and linear movements, until no more fine material passes through it.
Weigh the residue and express its mass as a percentage R1,of the quantity first placed on the sieve to the nearest 0.1 percent
Gently brush all the fine material off the base of the sieve.
Repeat the whole procedure using a fresh 10g sample to obtain R2. Then calculate R as the mean of R1 and R2 as a percentage, expressed to the nearest 0.1 percent. When the results differ by more than 1 percent absolute, carry out a third sieving and calculate the mean of the three values.

Result

Read and report the value of R, to the nearest of 0.1 percent, as the residue on the 90 micron sieve.

OTHER METHODS

Air Permeability Method

In air permeability test, The fineness of cement is represented or calculated by specific surface, i.e. total surface area in cm2 per gram or m2 per kilogram of cement and is measured by permeability apparatus.

This permeability apparatus essentially consists of :

Permeability Test Cell : Place where cement is stored and air pressure is applied.
Flowmeter : Flowmeter help to determine the quantity of air passing per second through its capillary tube per unit difference of pressure.
Manometer : Manometer help to measure the air pressure.

To determine the fineness, a cement sample of 2 cm height is placed on a perforated plate and air pressure is applied. The manometer is connected to the top of the permeability cell and the air is turned on. The lower end of the permeability cell is then slowly connected to the other end of the manometer. The rate of flow is so adjusted that the flowmeter shows a pressure difference (h2) of 30-50 cm. The reading (h1) in the manometer is recorded. The process is repeated till the ratio h1/h2 is constant.

The specific surface should not be less then following limits :

For Ordinary Portland Cement : The specific surface of this type of cement should not be less than 225 m2/kg.
For Rapid Hardening Cement : The specific surface of this type of cement should not be less than 325 m2/kg.
For Portland Puzzolana Cement : The specific surface of this type of cement should not be less than 300 m2/kg.

The Sedimentation Method

The turbidometer is a apparatus used to estimate the surface area of one gram of cement. The cement is uniformly in a rectangular glass tank filled with kerosene. Then, parallel light rays are passed through the solution which strike the sensitivity plate of a photoelectric cell. The turbidity of the solution at a given instant is measured by taking readings of the current generated by the cell. By recording the readings at regular intervals while the particles are falling in the solution, it is possible to secure information regarding the grading in surface area and in size of particle. Readings are expressed in cm2/g.

DESIGN OF SLAB (IS:456-:2000)

noreply@blogger.com (Rizwan Ahmad) — Sun, 03 Sep 2017 17:01:00 +0000

STEPS FOR DESIGN OF SLABS

Slabs form floors and roofs of building. They are generally assumed to carry uniformly distributed loads. Slabs are generally designed on the assumption that they consists of a number of beams of breadth ‘one meter’. The following steps are used in designing a slab :

Effective Span

The effective span of a simply supported slab shall be taken as follow

L = clear span + d (effective depth )
L = Center to center distance between the support.

Thickness of Slab

Maximum values of span to depth ratio for slab.

Type of slab	Ratio of span to depth (L/D)
Simply supported slab spanning in one direction (one way slab)	30
Continuous slab spanning in one direction (one way slab)	35
Simply supported slab spanning in two directions (two way slab)	35
Continuous slab spanning in two directions(two way slab)	40
Cantilever slabs	12

Reinforcement

The reinforcement for a one way slab consists of main bars and distribution bars (temperatures bars). These two sets of bars form a mesh of reinforcement.

a) Main Bars : This is calculated by equating moment of resistance and max. bending moment.

When Fe 415 grade steel is used,

The minimum reinforcement shall not be less than 0.12% of the gross sectional area.

The diameter of main bars may be 8 mm to 10 mm is used or shall not exceed one eight of the thickness of the slab.

For Fe 250 grade steel is used,

The minimum reinforcement shall not be less than 0.15% of the gross sectional area.

The diameter of main bars may be 10 mm to 12 mm is used.

b) Distribution Bars : these are reinforcement provided running at right angles to the main bars in order to distributes the load and the temperature and shrinkage stresses.

When Fe 415 grade steel is used, the minimum reinforcement shall not be less than 0.12% of the gross sectional area. The diameter of distribution bars may be 8 mm is used.

For Fe 250 grade steel is used, the minimum reinforcement shall not be less than 0.12% of the gross sectional area. The diameter of distribution bars may be 6 mm to 8 mm is used.

c) Spacing : the gap between the two consecutive reinforcement bars is called spacing.

maximum spacing of main bars : shall not exceed 3 times the effective depth of the slab or not exceed 300 mm.

maximum spacing of distribution bars : shall not exceed 5 times the effective depth of the slab or not exceed 300 mm.

note : The minimum spacing of bars shall not be less than 75 mm for satisfactory concreting

d) Clear Cover

The minimum cover to outside of main bars shall not be less than the following:

15 mm and

Diameter of the main bar.

Steps In Design Of Slab :

1. Assume the suitable bearing (not less than 100 mm) find the span between centre of bearing.

2. Assume the thickness of slab (take 40 mm per meter run of the span.

3. Find the effective span which is lesser of

distance between centres of bearings.

clear span and effective depth.

4. Find the dead load and the live load per square meter of slab.

5. Determine the maximum bending moment for a one meter wide strip of the slab.

The maximum bending moment per meter width of slab,

Where,
w = total load intensity per square meter of the slab.

6. Equating the moment of resistance to the maximum bending moment and find the effective depth required for flexural strength consideration.

7. calculate the main reinforcement per metre width of the slab.

for M15 concrete lever arm = 0.87d

8. Spacing of bar =

IS SPECIFICATION FOR RCC SLAB DESIGN

noreply@blogger.com (Rizwan Ahmad) — Sun, 03 Sep 2017 12:06:00 +0000

RCC SLAB DESIGN SPECIFICATION :

Guidelines for RCC slab design for depth of slab, loads on slab, reinforcement guide for one-way and two-way slabs have been tried to present here. Following are the RCC Slab Design and Detailing guidelines.

1. Effective Span Of a Slab :

Unless otherwise specified, the effective span of a slab shall be taken as follow.

a) Simply supported slab : Effective span of slab shall not be more than of the two.

L = clear span + d (effective depth )
L = Center to center distance between the support.

b) effective cantilever length : Effective length shall be taken as its length to the face of the support plus the half the effective depth except where it forms the end of the continuous slab where the length up to the centre of the support shall be taken.

c) Bearing for a slab : The length of bearing to support a slab on the wall may be from 100 mm to 150 mm.

2. Depth Of Slab:

The depth of slab depends on bending moment and deflection of a slab. The trail depth can be obtained for different types of slab by using :

Effective depth d= Span /((L/d)_Basic x modification factor).

for one way simply supported slab :

Effective depth d= Span /20 x modification factor).

for one way continuous slab (both end cont.)

Effective depth d= Span /23 x modification factor).

For one way continuous slab (one end cont.)

Effective depth d= Span /26 x modification factor).

For cantilever slab :

Effective depth d= Span /26 x modification factor).

For obtaining modification factor, the percentage of steel for slab can be assumed from 0.2 to 0.5%.

For two way slab, the shorter of the two spans should be used for determining the span to effective depth ratios. Two way slab of shorter span up to 3.5 m the span to overall depth ratios given below may generally be assumed to satisfy vertical deflection limits for loading class is up to 3.5 KN/m²

Types of support	Fe-250 (mild steel)	Fe-415 (high strength steel)
Simply supported	L/35	L/28
Continuous support	L/40	L/32

Or, the following rules can be used:

Two way simply supported slab d=(L/20) to (L/30)

Two way restrained slab d=(L/30) to (L/32)

3. Load On Slab:

The following types of load working on a slab is given as :

Dead load
floor finish
and live load

Dead load : It is the self weight of building can be calculated by the formula D x 25 kN/m² ( Where D is thickness of slab in m)

Floor finish (Assumed as)= 1 to 2 kN/m²

Live load (Assumed as) = 3 to 5 kN/m² (depending on the occupancy of the building)

4. Reinforcement For Slab As Per IS 456: 2000

The reinforcement for a one way slab consists of main bars and distribution bars (temperatures bars). These two sets of bars form a mesh of reinforcement.

a) Main Bars : This is calculated by equating moment of resistance and max. bending moment.

When Fe 415 grade steel is used

The minimum reinforcement shall not be less than 0.12% of the gross sectional area.

The diameter of main bars may be 8 mm to 10 mm is used or shall not exceed one eight of the thickness of the slab.

For Fe 250 grade steel is used,

The minimum reinforcement shall not be less than 0.15% of the gross sectional area.

The diameter of main bars may be 10 mm to 12 mm is used.

b) Distribution Bars : these are reinforcement provided running at right angles to the main bars in order to distributes the load and the temperature and shrinkage stresses.

When Fe 415 grade steel is used, the minimum reinforcement shall not be less than 0.12% of the gross sectional area. The diameter of distribution bars may be 8 mm is used.

For Fe 250 grade steel is used, the minimum reinforcement shall not be less than 0.12% of the gross sectional area. The diameter of distribution bars may be 6 mm to 8 mm is used.

c) Spacing : the gap between the two consecutive reinforcement bars.

maximum spacing of main bars : shall not exceed 3 times the effective depth of the slab or not exceed 300 mm.

maximum spacing of distribution bars : shall not exceed 5 times the effective depth of the slab or not exceed 300 mm.

note : The minimum spacing of bars shall not be less than 75 mm for satisfactory concreting

d) Cover To Slab Reinforcement :

The minimum cover to outside of the main bars shall not be less than 15 mm or diameter of main bars.

HOW TO PERFORM CONSISTENCY TEST OF CEMENT ?

noreply@blogger.com (Rizwan Ahmad) — Fri, 01 Sep 2017 18:42:00 +0000

Consistency test is used to estimate the quantity of mixing water to form a paste of normal consistency. The normal consistency defined as that percentage water requirement of the cement paste, the viscosity of which will be such that the Vicat’s plunger penetrates up to a point 5 to 7 mm from the bottom of the Vicat’s mould.

FACTOR AFFECTING FINENESS OF CEMENT

1. The chemical composition and the degree of calcination influence the hardness of the clinker and consequently the fineness to which the cement is ground.

2. Clinker, high in iron or silica, is apt to be hard and difficult to grind. The same is true with a hard burned clinker.

3. Fineness is also influenced by the time of grinding and the character of the pulverizing machinery. It has been found that cement becomes finer with age provided it does not absorb too much moisture. This is probably due to the decrepitation of the coarser grains resulting from the hydration of the embedded lime particles.

TEST IMPORTANCE

Finer the cement, more is the strength since surface area for hydration will be large. With increase in fineness, the early development of strength is enhanced but the ultimate strength is not affected. An increase in the fineness of the cement increases the cohesiveness of the concrete mix and thus reduces the amount of water which separates to the top of a lift (bleeding), particularly while compacting with vibrators. However, if the cement is ground beyond a certain limit, its cementative properties are affected due to the prehydration by atmospheric moisture. Finer cement reacts more strongly in alkali reactive aggregate. Also, the water requirement and workability will be more leading to higher drying shrinkage and cracking.

TEST PROCEDURE

Objective

To determine the water requirement of the cement paste with normal consistency.

Apparatus

Vicat’s Apparatus

Sample/Specimen

To makes a viscous paste as a sample, 300 g of cement is mixed with 25 per cent water.

Procedure

The paste is filled in the mould of Vicat’s apparatus and the surface of the filled paste is smoothened and leveled.

A square needle 10 mm x 10 mm attached to the plunger is then lowered gently over the cement paste surface and is released quickly. The plunger pierces the cement paste.
The reading on the attached scale is recorded.

When the reading is 5-7 mm from the bottom of the mould, the amount of water added is considered to be the correct percentage of water for normal consistency.

Result

The normal consistency of cement paste is achieved as a result.

MANUFACTURING OF ORDINARY PORTLAND CEMENT

noreply@blogger.com (Rizwan Ahmad) — Fri, 01 Sep 2017 10:00:00 +0000

RAW MATERIALS

Calcareous (material having content of lime)
Argillaceous (material having content of silica and alumina)
Gypsum

Composition Of Raw Materials :

Lime (CaO)	60 to 67%
Silica (SiO2)	17 to 25%
Alumina (Al2O3)	3 to 8%
Iron oxide (Fe2O3)	0.5 to 6%
Magnesia (MgO)	0.1 to 4%
Sulphur trioxide (SO3)	1 to 3%
Soda and/or Potash (Na2O+K2O)	0.5 to 1.3%

MANUFACTURING PROCESSES OF CEMENT (OPC)

Cement is manufactured by the following two processes :

Dry Process

Wet Process

These two processes differ in operation but fundamentals of both these processes are same.

Crushing and grinding
Mixing the material in proportion
Heating the prepared mixture in rotary kiln
Grinding the heated product known as clinker
Mixing and grinding of cement clinker with gypsum

DRY PROCESS

The dry process is adopted when the raw materials are quite hard. The process is slow and the product is costly.

Steps involve in manufacturing of portland cement by dry method :

Limestone and clay are ground to fine powder separately and are mixed. Water is added to make a thick paste.

The cakes of this paste, which contain about 14 per cent of moisture, are dried and are charged into rotary kiln.

Rotary Kiln

The product obtained after calcination in rotary kiln is called clinker. The clinker is obtained as a result of incipient fusion and sintering at a temperature of about 1400°- 1500°C.
Because ferric oxide has lower melting point than the other oxides, it acts as a flux. Aeration of cement clinker, which is commonly practised to slake free lime, also causes an absorption of some moisture and carbon dioxide. Absorption of moisture tends to decrease the setting whereas that of carbon dioxide accelerates setting.
The clinker is cooled rapidly to preserve the meta stable compounds and their solid solutions dispersion of one solid in another which are made as the clinker is heated. Clinker is then cooled and ground in tube mills.
where 2-3% of gypsum is added. Generally, cement is stored in bags of 50 kg. The purpose of adding gypsum is to coat the cement particles by interfering with the process of hydration of the cement particles. This retards the setting of cement.

WET PROCESS

The operations in the wet process of cement manufacture are mixing, burning and grinding.

Step involve in the manufacturing of portland cement by wet process are :

The crushed raw materials are fed into ball mill and a little water is added. On operating the ball mill, the steel balls in it pulverize the raw materials which form a slurry with water.

This slurry is passed to storage tanks where the proportioning of the compounds is adjusted to ensure desired chemical composition. The corrected slurry having about 40 per cent moisture content, is then fed into rotary kiln where it loses moisture and forms into lumps.

These are finally burned at 1500-1600°C. The lumps change to clinker at this temperature. Clinker is cooled and then ground in tube mills. While grinding the clinker, about 3 per cent gypsum is added. The cement is then stored in storage tanks from where it is supplied.

SPLITTING TENSILE STRENGTH TEST OF CONCRETE (IS: 516)

noreply@blogger.com (Rizwan Ahmad) — Thu, 31 Aug 2017 21:04:00 +0000

SPLITTING TENSILE STRENGTH TEST OF CONCRETE

Tests shall be made at recognized ages of the test specimens, the most usual being 7 and 28 days. Where it may be necessary to obtain the early strengths, tests may be made at the ages of 24 hours ± ½ hour and 72 hours ± 2 hours. The ages shall be calculated from the time of the addition of water to the dry ingredients.Number of Specimens – At least three specimens, preferably from different batches, shall be made for testing at each selected age.

Objective

To determine the tensile strength of concrete

Apparatus

Testing Machine – The testing machine may be of any reliable type, of sufficient capacity for the tests and capable of applying the load at the rate specified in 5.5. The permissible error shall be not greater than ± 2 percent of the maximum load.Cylinders –The cylindrical mould shall be of 150 mm diameter and 300 mm height conforming to IS: 10086-1982 Weights and weighing devices, tool and containers for mixing, tamper(square in cross section) etc.

Sampling Of Material

Samples of aggregates for each batch of concrete shall be of the desired grading and shall be in an air-dried condition. The cement samples, on arrival at the laboratory, shall be thoroughly mixed dry either by hand or in a suitable mixer in such a manner as to ensure the greatest possible blending and uniformity in the material.

Proportioning

The proportions of the materials, including water, in concrete mixes used for determining the suitability of the materials available, shall be similar in all respects to those to be employed in the work.

Weighing

The quantities of cement, each size of aggregate, and water for each batch shall be determined by weight, to an accuracy of 0.1 percent of the total weight of the batch.

Mixing Concrete

The concrete shall be mixed by hand, or preferably, in a laboratory batch mixer, in such a manner as to avoid loss of water or other materials. Each batch of concrete shall be of such a size as to leave about 10 percent excess after moulding the desired number of test specimens.

Moulding

The cylindrical mould shall be of 150 mm diameter and 300 mm height conforming to IS: 10086-1982.

Compacting Of Concrete

Temping Bar : The tamping bar is a steel bar of 16 mm diameter , 60 cm long and bullet pointed at the lower end.

Hand Compaction

When compacting by hand, the standard tamping bar is used and the stroke of the bar should be distributed in a uniform manner. The number of strokes for each layer should not less than 30. The stroke should penetrate in to the underlying layer and the bottom layer should be rodded throughout its depth. After top layer has been compacted,the surface of the concrete should be finished level with the top of the mould,using a trowel and covered with a glass or metal plate to prevent evaporation.

Curing Of Specimen

The test specimen should be stored in a place at a temperature of 27° +/- 2°C for 24 +/- 0.5 hrs. from the time addition of water to the dry ingredients. After this period the specimen should be marked and removed from the woulds and immediately submerged in clean fresh water or saturated lime solution and kept there until taken out just prior to the test. The water or solution in witch the specimen s are kept should be renewed every seven days and should be maintained at a temperature of 27° +/- 2°c.Concrete cylinder 15 cm diameter &3 0cm long.

NOTE

Cast 6 cylinders (3 for split test &3 for compression test ).

Procedure

Take the wet specimen from water after 7 days of curing

Wipe out water from the surface of specimen

Draw diametrical lines on the two ends of the specimen to ensure that they are on the same axial place.

Note the weight and dimension of the specimen.

Set the compression testing machine for the required range.

Keep are plywood strip on the lower plate and place the specimen.

Align the specimen so that the lines marked on the ends are vertical and centered over the bottom plate.

Place the other plywood strip above the specimen.

Bring down the upper plate to touch the plywood strip.

Apply the load continuously without shock at a rate of approximately 14-21kg/cm2/minute (Which corresponds to a total load of 9900kg/minute to 14850kg/minute)

Note down the breaking load(P)

Calculation

As per IS: 456,

Split tensile strength of concrete.= 0.7Fck

The splitting tensile strength is calculated using the formula :

Tsp = 2P/ pi DL

Where

P = applied load

D = diameter of the specimen

L = length of the specimen

Therefore,

P = Tsp x pi DL/2

Expected load = P x f.sRange to be selected is…………..

Split Tensile Strength

T = 2P/ pi DL

Result

Splitting tensile strength of given concrete =……………….N/mm²

HOW TO PERFORM THE VOLUMETRIC SHRINKAGE TEST OF TIMBER (IS : 1708 ( Part 3) – 1986) ?

noreply@blogger.com (Rizwan Ahmad) — Thu, 31 Aug 2017 17:52:00 +0000

VOLUMETRIC SHRINKAGE TEST OF TIMBER

This test is performed to determine the amount of volumetric shrinkage happen in timber when it moves from wet to dry condition. Volumetric shrinkage tells how much a wood species will shrink, but it doesn’t indicate the direction of the shrinkage. The two primary planes or surfaces of wood where shrinkage takes place are across the radial plane, and across the tangential plane, corresponding to radial shrinkage, and tangential shrinkage; these two values, when combined, should roughly add up to the volumetric shrinkage.

OBJECTIVE

To determine the volumetric shrinkage of timber.

APPARATUS :

Weighing Balance : 0-10 kg.

Oven : maintain a temperature of 105- 110°C

PREPARATION OF SAMPLE :

The specimens of timber are prepared with 5 × 5 × 15 cm or 2 × 2 × 6 cm sizes.

PROCEDURE :

The specimen is weighed initially (usually green) and the volume determined.

A suitable vessel, half filled with water, is kept on the pan of a weighing balance and weighed.

The specimen is then completely dipped in water by means of a needle and weighed again. The difference of the two readings is volume of the specimen.

The specimen is taken out of the water, wiped with dry cloth, end-coated by immersion in hot paraffin, allowed to air-season under room conditions and weighed periodically until moisture content of about 12 per cent is reached. The volume is determined again.

The specimen is then kept in an oven at 103° 2°C until an approximately constant weight is reached.

After oven-drying, the specimen is again weighed and, while still warm, is immersed in hot paraffin wax bath,care being taken to remove it quickly to ensure only a thin coating.

The volume of the paraffin-coated specimen is determined by immersion as before.

CALCULATION :

Volumetric shrinkage form initial condition to required dry condition =

Moisture Content =

Oven Dry Specific Gravity =

where

W1 and V1 = Initial weight and initial volume

Wr and Vr = Weight and volume at the initial required dry condition at r per cent moisture content.

W0 and V0 = Final weight and final volume

WHAT IS MEANT BY HYDRATION OF CEMENT ?

noreply@blogger.com (Rizwan Ahmad) — Thu, 31 Aug 2017 17:17:00 +0000

HYDRATION OF CEMENT

The chemical reaction between cement and water is known as hydration of cement. The reaction takes place between the active components of cement and water.

Active components are :

Tetracalcium Aluminate (C4AF)

Tricalcium Aluminate (C3A)

Tricalcium Silicate (C3S)

Dicalcium Silicate C2S)

Gypsum (CSH2)

The factors responsible for the physical properties of concrete are the extent of hydration of cement and the resultant microstructure of the hydrated cement. When the cement comes in contact with water, the hydration products start depositing on the outer periphery of the nucleus of hydrated cement. This reaction proceeds slowly for 2-5 hours and is called induction or dormant period. As the hydration proceeds, the deposit of hydration products on the original cement grain makes the diffusion of water to unhydrated nucleus more and more difficult, consequently reducing the rate of hydration with time. At any stage of hydration, the cement paste consists of gel (a fine-grained product of hydration having large surface area collectively), the unreacted cement, calcium hydroxide, water and some minor compounds.

The crystals of the various resulting compounds gradually fill the space originally occupied by water, resulting in the stiffening of the mass and subsequent development of the strength.

The hardened cement paste :

Hardened cement paste consists of the following:

Ettringite - 15 to 20%

Calcium silicate hydrates, CSH - 50 to 60%

Calcium hydroxide (lime) - 20 to 25%

Voids - 5 to 6% (in the form of capillary voids and entrapped and entrained air)

RATE OF HYDRATION

The reaction of compound C3A with water is very fast and is responsible for flash setting of cement (stiffening without strength development) and thus it will prevent the hydration of C3S and C2S. However, calcium sulphate (CaSO4) present in the clinker dissolves immediately in water and forms insolubleB calcium sulphoaluminate. It deposits on the surface of C3A forming a colloidal membrane and consequently retards the hydration of C3A. The amount of CaSO4 is adjusted to leave a little excess of C3A to hydrate directly. This membrane in the process breaks because of the pressure of the compounds formed during hydration and then again C3A becomes active in the reaction.

Contribution of cement compounds to strength of cement with increasing age.

The hardening of C3S can be said to be catalyzed by C3A and C3S becomes solely responsible for gain of strength up to 28 days by growth and interlocking of C-S-H gel. The increase in strength at later age is due to hydration of C2S.

Rate of hydration of pure cement compound

COMPOSITION OF ORDINARY PORTLAND CEMENT (IS: 269)

noreply@blogger.com (Rizwan Ahmad) — Thu, 31 Aug 2017 09:53:00 +0000

COMPOSITION OF ORDINARY PORTLAND CEMENT

This is the cement used for normal concrete construction. It has adhesive and cohesive properties so as to render and to form good bond with other material. It solidifies when mixed with water. It is the most active binding medium and is perhaps the most scientifically controlled component in concrete. Cement is obtained by burning a mixture of the following materials in a define proportion :

Siliceous materials

Argilleceus materials

Calcareous materials

The temperature of which the mixture must be burnt is about 1400°C. The clinker so is cooled and powdered to the required fineness. The product so obtained is called cement.

COMPOSITION

Lime (CaO)	60 to 67%
Silica (SiO2)	17 to 25%
Alumina (Al2O3)	3 to 8%
Iron oxide (Fe2O3)	0.5 to 6%
Magnesia (MgO)	0.1 to 4%
Sulphur trioxide (SO3)	1 to 3%
Soda and/or Potash (Na2O+K2O)	0.5 to 1.3%

The above constituent mixing together to form raw material undergo a chemical reaction during burning and fusion, the compounds formed in the burning process have the properties of setting and hardening in the presence of water. They are known as Bogue compounds which are given below :

Compound	Abbreviated designation
Tricalcium silicate (3CaO.SiO2)	C3S
Dicalcium silicate (2CaO.SiO2)	C2S
Tricalcium aluminate (3CaO.Al2O3)	C3A
Tetracalcium aluminoferrite (4CaO.Al2O3.Fe2O3)	C4AF

The properties of Portland cement varies markedly with the proportions of the above four compounds, reflecting substantial difference between their individual behaviour.

FUNCTION OF FOLLOWING COMPOUNDS

Tricalcium Silicate

Tricalcium silicate is supposed to be the best cementing material and is well burnt cement. It is about 25-50% (normally about 40 per cent) of cement.

It renders the clinker easier to grind, increases resistance to freezing and thawing, hydrates rapidly generating high heat and develops an early hardness and strength.

However, raising of C3S content beyond the specified limits increases the heat of hydration and solubility of cement in water.

The hydrolysis of C3S is mainly responsible for 7 day strength and hardness.

The heat of hydration is 500 J/g.

Dicalcium Silicate

Dicalcium silicate is about 25-40% (normally about 32 per cent) of cement. It hydrates and hardens slowly and takes long time to add to the strength (after a year or more).

It imparts resistance to chemical attack.

Raising of C2S content renders clinker harder to grind, reduces early strength, decreases resistance to freezing and thawing at early ages and decreases heat of hydration.

The heat of hydration is 260 J/g.

Tricalcium Aluminate

Tricalcium aluminate is about 5-11% (normally about 10.5 per cent) of cement.

It rapidly reacts with water and is responsible for flash set of finely grounded clinker. The rapidity of action is regulated by the addition of 2-3% of gypsum at the time of grinding cement.

Tricalcium aluminate is responsible for the initial set, high heat of hydration and has greater tendency to volume changes causing cracking.

Raising the C3A content reduces the setting time, weakens resistance to sulphate attack and lowers the ultimate strength, heat of hydration and contraction during air hardening.

The heat of hydration of 865 J/g.

Tetracalcium Alumino Ferrite

Tetacalcium allumino ferrite is about 8–14% (normally about 9 per cent) of cement.

It is responsible for flash set but generates less heat.

It has poorest cementing value.

Raising the C4AF content reduces the strength slightly.

The heat of hydration is 420 J/g.

HOW TO PERFORM STATIC BENDING STRENGTH TEST OF TIMBER ?

noreply@blogger.com (Rizwan Ahmad) — Wed, 30 Aug 2017 19:22:00 +0000

STATIC BENDING STRENGTH TEST

BY ONE POINT LOAD TEST :

OBJECTIVE

To determine the bending strength of timber by one point load test under static load.

EQUIPMENT

Static bending test equipment.

SAMPLE/SPECIMEN

The specimen may be 50 × 50 × 750 mm or 20 × 20 × 300 mm prepared for test.

PROCEDURE

The test specimen is supported on the rig. The load is applied continuously at a constant rate of 2.5 mm per minute in case of 50 × 50 × 750 mm and 1.0 mm per minute in case of 20 × 20 × 300 mm.

Deflections of the neutral plane at the centre of the length are measured with respect to the points in the neutral plane above the supports. Deflections of the neutral axis are measured at the centre of the beam.

Deflection is measured at suitable load intervals such that about 8–10 readings are available up to limit of proportionality.

Beyond the limit of proportionality up to maximum load or beyond maximum load the test is continued until a deflection of 150 mm for 750 mm and 60 mm for 300 mm specimens is reached. or the specimen fails to support 1000 N for 50 × 50 × 750 mm or 200 N for 20 × 20 × 300 mm specimens, whichever is earlier.

The failure of the specimen is recorded according to its appearance and development.

The readings of deflections and the load recorded and a load deflection curve is drawn.

CALCULATION

The various characteristics are determined by the following formula and from the load-deflection curve.

where

P = load at the limit of proportionality, the point in load-deflection curve at which the graph deviates from the straight line.

l = length of specimen

b = width of specimen

h = height of the specimen

P = maximum load

delta = deflection at the limit of proportionality

C = area constant

A = area of load-deflection curve up to limit of proportionality

A = area up to maximum load

A = area up to the final reading when total work is required

WHAT ARE THE DIFFERENT FORM OF BRICKS ON THE BASIS ON THEIR SHAPE AND GEOMETRY ?

noreply@blogger.com (Rizwan Ahmad) — Wed, 30 Aug 2017 17:22:00 +0000

DIFFERENT FORM OF BRICK ON THE BASIS OF THEIR SHAPE

Bricks can be classified on the basis of their geometry and shape. There are bricks in the form of round ended, bull nosed, perforated, coping, hollow, compass, cornice, cant, double cant, king closer, queen closer, engineering bricks etc. Every one of these also has a unique function and characteristic that allows you to have the right brick at the right place.

ROUND ENDED BRICK

Round ended brick are used to construct open drains.

BULL NOSED BRICK

A brick moulded with a rounded angle is termed as a bullnose. It is used for a rounded quoin and to construct open drains. A connection which is formed when a wall takes a turn is known as a quoin. The centre of the curved portion is situated on the long centre-line of brick.

CANT BRICK

The splay or cant bricks are made for jambs of doors and windows.

DOUBLE CANT BRICK

The double cant brick is used for octagonal pillars

CORNICE BRICK

Cornice bricks is used from architectural point of view.

COMPASS BRICK

A compass brick tapering in both directions along its length used to construction of furnaces.

PERFORATED BRICK

Perforated bricks contain cylindrical holes throughout their thickness. They may be circular, square rectangular or any other regular shape in cross-section. The distance between the side of brick and edge of perforation should not be less than 15mm. The distance between the edges of successive perforations should preferably be not less than 10mm. The water absorption after immersion for 24 hours in water should not exceed 15 percent by weight. The compressive strength of perforated bricks should not be less than 7 N/mm² on gross area. These bricks are light in weight and they require less quantity of clay for their preparation. Perforated brick is well burned brick, but is not sound proof. The perforated bricks are used in the construction of panels for lightweight structures and multi-storeyed framed structures. countries like India, the bricks with perforations of about 30 to 45 per cent of the total area of the corresponding face of the brick would offer adequate thermal insulation property.

HOLLOW BRICK

These are also known as the cellular or cavity bricks. Such bricks have wall thickness of about 20mm to 25mm. They are prepared from special homogeneous clay. These are about l/3rd the weight of normal bricks and are sound and heat proof, but are not suitable where concentrated loads are expected. They are used in the construction of partitioning.

COPING BRICK

Top most bricks course of parapets is made with coping bricks. These drain off the water from the parapets. Brick is used at plinth level and for door and window jambs.

QUEEN CLOSER BRICK

When the brick is cut along the length, it is called queen closer and when cut at one end by half header and half stretcher, it is known as king closer.

KING CLOSER BRICK

when the brick cut at one end by half header and half stretcher, it is known as king closer.

PURPOSE MADE BRICK

In order to achieve certain purpose, these types of bricks are made.

Engineering Brick

The engineering bricks having adiquate strength, 0 to 80 N/mm2 and water absorption about 4 to 6 per cent, can be prepared from specially selected earth for use in constructions where high durability, compression strength and adequate resistance to sudden shocks are required.

Engineering bricks offer excellent load bearing capacity damp-proof characteristics and chemical resisting properties. These bricks are used in specific projects and can cost more than regular or traditional bricks.

Other Brick

The splay or cant bricks are made for jambs of doors and windows. The arch bricks are made of wedge shape to keep mortar joint of uniform thickness. The ornamental bricks are prepared for corbels, cornices, etc.

Related Post:-

DIMENSION TEST OF BUILDING BRICK(IS: 1077)

WATER ABSORPTION TEST OF BRICK (IS: 3495 (PART 2))

EFFLORESCENCE TEST OF BUILDING BRICK (IS: 3495 (PART 3)

WARPAGE TEST OF EARTHEN BRICK (IS-3495 (PART-4))

COMPRESSIVE STRENGTH TEST FOR BRICKS (IS-3495 (PART-1))

HEAVY DUTY BURNT CLAY BUILDING BRICK ( IS: 2180 )

WHAT ARE THE VARIOUS TYPE OF BRICKS USED IN MASONRY ?

WHAT ARE THE ADMIXTURE TO MANUFACTURE OF BRICK ?

WHAT ARE THE METHOD USE TO MANUFACTURE EARTHEN BRICK ?

WHAT ARE THE INGREDIENTS OF GOOD BRICK EARTH ?

DIFFERENT TYPES OF BRICK USES IN BRICK MASONRY WORK

noreply@blogger.com (Rizwan Ahmad) — Wed, 30 Aug 2017 17:08:00 +0000

DIFFERENT TYPES OF BRICK USES IN BRICK MASONRY

bricks are used as siding in the building industry due in part to its important characteristics and just because it can be a good affordable option. Below we summarize the benefits and applications of the most commonly used type of bricks.

various types of bricks uses in masonry.

1) Common Burnt Clay Bricks

2) concrete Bricks

3) Sand Lime Bricks (Calcium Silicate Bricks)

4) Fly ash Clay Bricks

5) Engineering Bricks

1) Common Burnt Clay Bricks

Common burnt clay bricks are formed by pressing in molds. Then these bricks are dried and fired in a kiln. Common burnt clay bricks are used in general work with no special attractive appearances. When these bricks are used in walls, they require plastering or rendering.

2) Concrete Bricks

Concrete brick is a mixture of cement and aggregate, usually sand, formed in molds and cured. Certain mineral colours are added to produce a concrete brick resembling clay. these are used in hou

3) Sand Lime Bricks

Sand-lime brick is a product that uses lime instead of cement. Sand lime bricks are made by mixing sand, fly ash and lime followed by a chemical process during wet mixing.It is usually a white brick made of lime and selected sands, cast in molds and cured. These bricks can offer advantages over clay bricks such as:

1) color appearance is gray instead of the regular reddish color.

2) offers excellent strength as a load-bearing member.

3) shape of these bricks is uniform and presents a smoother finish that doesn’t require plastering.

4) Fly Ash Clay Bricks

Fly ash clay bricks are manufactured with clay and fly ash, at about 1,000 degrees C. Some studies have shown that these bricks tend to fail poor produce pop-outs, when bricks come into contact with moisture and water, causing the bricks to expand.

5) Engineering Bricks

WATER ABSORPTION TEST OF BRICK (IS: 3495 (PART 2))

EFFLORESCENCE TEST OF BUILDING BRICK (IS: 3495 (PART 3)

WARPAGE TEST OF EARTHEN BRICK (IS-3495 (PART-4))

COMPRESSIVE STRENGTH TEST FOR BRICKS (IS-3495 (PART-1))

HEAVY DUTY BURNT CLAY BUILDING BRICK ( IS: 2180 )

WHAT ARE THE VARIOUS TYPE OF BRICKS USED IN MASONRY ?

WHAT ARE THE ADMIXTURE TO MANUFACTURE OF BRICK ?

WHAT ARE THE METHOD USE TO MANUFACTURE EARTHEN BRICK ?

WHAT ARE THE INGREDIENTS OF GOOD BRICK EARTH ?

WHAT ARE THE CLASSIFICATION OF TIMBER ON THE BASIS OF GRADING (IS: 6534-1971)

noreply@blogger.com (Rizwan Ahmad) — Wed, 30 Aug 2017 15:58:00 +0000

TIMBER CLASSIFICATION ON THE BASIS OF GRADING

The terms timber and wood are often used synonymously, but they have distinct meanings in the building industry. Wood is the hard, fibrous material that makes up the tree under the bark, whereas timber may be used in various engineering works. The classification of timber based on grading which is given in IS: 6534.

STRUCTURAL GRADING

this type of grading is also known as stress grading. However, there is a small distinction between the two. Structural grading refers to the principle by which the material is gradedb on the basis of visible defects which have known effects on the strength properties of the material. Stress grading refers to the principle by which the material is graded by consideration of maximum principle stresses to which it can be subjected. Structural grading is further divided as:

1. Grading based on known effects of defects and estimating accumulative value.

2. Machine grading.

COMMERCIAL GRADING

Commercial grading also known as yard grading or utility grading refers to the principle by which the material is graded by consideration of usefulness of the material and price factors.

Commercial grading is further divided in the following classes:

Grade A

This classification is based on dimensions and general appearance. The dimensions of lengths, widths and thicknesses of converted materials are measured. This system is prevalent is Kerala and Mysore.

Grade B

This classification is based on the best ultimate use of the material. Such a system is mostly in Andhra Pradesh and some parts of Tamil Nadu. Here, each grade is further divided into A, B and C classes to indicate occurrence of defects. Only two lengths are recognized, long (L) which is 5m and above, and short(S) that is under 5m. Each log is stamped such as BAL (Beam, A-class, long), PBS (Plank, B-class, short), etc. Some times another letter is also added indicating the species, e.g. T for teak.

Grade C

This classification is based on qualitative evaluation of defects and rough estimate of out-turn of utilizable material. It is prevalent in Madhya Pradesh.

Grade D

This classification is based on evaluation of units of defects and fixing the permissible number of standard volume of area or the material in each grade. This system is prevalent in Bombay region and is increasingly adopted in Indian Standards and is recognized internationally.

SPECIFICATION FOR HEAVY DUTY BURNT CLAY BUILDING BRICK ( IS: 2180 )

noreply@blogger.com (Rizwan Ahmad) — Wed, 30 Aug 2017 15:51:00 +0000

HEAVY DUTY BURNT CLAY BUILDING BRICKS

QUALITY

1) These bricks should have uniform texture and colour.

2) The surface of these bricks should be smooth and rectangular, with parallel, sharp and straight edges and square corners.

3. Heavy duty bricks should be free from flaws, cracks and stones.

4) No impression should be left on the heavy duty bricks when a scratch is made by a finger nail.

5) When broken fractured surface of the brick shall show a uniformly dense structure, free from large voids and lime particles.

6) Water absorption of these bricks should be 10% of its dry weight when immersed in cold water for

24 hours.

7) A metallic or ringing sound should come when two bricks are struck against each other.

SPECIFICATION

Water Absorption

Water absorption of these brick should not be more than 10 per cent after 24 hours immersion in water.

Efflorescence

Should be nil

Bulk Density

Shall not be less than 2500 kg/m3.

Compressive Strength

Heavy duty bricks are classified into two categories on the basis of compressive strength namely class 40 and class 45 each one have their different specification.

a) CLASS 40

Minimum average compressive strength of heavy duty burnt clay bricks of class 40 should not be less than 40 N/mm2 and not greater than 45N/mm2. When tested for any individual brick, shall not fall below the minimum average compressive strength specified for the corresponding class of brick by more than 20%.

b) CLASS 45

Minimum average compressive strength of heavy duty burnt clay bricks of class 45 should not be less than 45 N/mm2. When tested for any individual brick, shall not fall below the minimum average compressive strength specified for the corresponding class of brick by more than 20%.

DIMENSION AND TOLERANCE

Class 40 (40-45 N/mm2)

Dimension

Length- 190 mm

Width- 90 mm

Height- 90 mm (40 mm for no frog brick)

Class 45 (45 N/mm2)

Dimension

Length- 190 mm

Width- 90 mm

Height- 90 mm( 40 mm for no frog brick)

Heavy duty burnt clay brick of class 45 further subdivided into subclasses A and B based on tolerance.

Tolarence

Subclass A a) length- 6 mm (less or more)

b) width- 3 mm (less or more)

Subclass B a) length- 15 mm (less or more)

b) width- 7 mm(less or more)

HOW TO CLASSIFY TIMBER ON THE BASIS OF POSITION AND DURABILITY (IS: 399)

noreply@blogger.com (Rizwan Ahmad) — Wed, 30 Aug 2017 15:23:00 +0000

CLASSIFICATION OF TIMBER

POSITION BASIS:

Standing Timber : It means that the living tree.

Rough Timber : Form a part of felled tree.

Lumber : lumber are the logs of timber sown into planks, posts.

MODULUS OF ELASTICITY BASIS:

The species of timber recommended for constructional

purpose are classified as:-

Group A

Modulus of elasticity in bending above 12.5 kN/mm2

Group B

Modulus of elasticity in bending above 9.8 kN/mm2 and below 12.5 kN/mm2

Group C

Modulus of elasticity in bending above 5.6 kN/mm2 and below 9.8 kN/mm2.

AVAILABILITY BASIS:

According to availability, timber can be of three

grades, namely X, Y and Z.

Grade X

Most common, 1415 m3 or more per year

Grade Y
Common, 355 m3 to 1415 m3 per year

Grade Z
Less common, below 355 m3 per year

This is based upon the figures supplied by the forest departments.

DURABILITY BASIS:

Test specimens of size 600 × 50 × 50 mm are buried in the ground to half their lengths. The condition of the specimen at various intervals of time are noted and from these observations their average life is calculated. Timbers are classified based upon such observations as of:

a) High Durability: Average life of 120 months and

over.

b)Modrate Durability: Average life of less than 120

months but of 60 months or more.

c)Low Durability: Average life of less than 60

months.

SEASONING CHARACTERISTICS BASIS:

Timbers are classified depending upon their behaviour

to cracking and splitting during normal air-seasoning

practice under three categories.

a) High Refractory: are slow and difficult to season

free from defects.

b) Moderate Refractory: protection is given against

rapid drying.

c) Low Refractory: These can be rapidly seasoned

free from defects.

TREATABILITY BASIS:

This classification is based upon the resistance offered by the heartwood of a species to preservatives under a working pressure of 1.05 N/mm2 as:

(a) Easily treatable.
(b) Treatable but complete preservation not easily

obtained.

(d) Refractory to treatment.

(e) Very refractory to treatment, penetration of

preservative being practically nil from the

sides and ends.

CLASSIFICATION OF CLAY ON THE BASIS OF RESISTANCE TO HIGH TEMPERATURE

noreply@blogger.com (Rizwan Ahmad) — Tue, 29 Aug 2017 18:13:00 +0000

CLASSIFICATION OF CLAY

Clay is the finess material of soil with finess size 0.002 mm.after the application of water it shows plastic behaviour. It is soft, moist, earthy material that made from eroded rocks. It can be moulded when wet, and is dried and baked to make bricks, pottery, and ceramics.
Bulk specific gravity of clay brick ranges from 1.6 to 2.5.

Clay is the most Important Raw Material Used For Making Bricks. It is An Earthen mineral mass or fragmentary rock capable of mixing with water and forming a plastic viscous mass which has a property of retaining it shape with Moulded and dried. when such mass are heated to redness, they acquire hardness and strength. the purest clay consist mainly of kaolinite with small quantity of minerals such as quartz mica, felspar, calcite, magnesite etc. by there origin clay are subdivided as residual and transported clays. residual clay, known as kaolin or china clay, are formed from the decay of underlying rocks and are used for making pottery. transported or sedimentary clays result from the action of weathering agencies. these are more disperse, contain impurities, and free from large particles of mother rocks.

CLASSIFICATION :

On The Basis Of Resistance To High Temperature :

on the basis of resistance to high temperatures( more than 1580°C),clay are classified as

Refractory Clay

High melting clay

Low melting clay

Refractory Clay : The refractory clays are highly Disperse and Very Plastic. These have high content of alumina and low content of impurities, such as fe2O3, tending to lower the refractoriness.

Note : refractory clay burned at 1000 °C-1400 °C and crushed

High Melting Clay : It have high refractoriness and contain small amount of impurities such as quartz, felspar, mica,calcium carbonate and magnessium carbonate. These are used for manufacturing facing bricks, floor tiles, sewer pipes etc.

Low melting clay : It have refractoriness less than 1350 °C and have varying compsition. These are used to manufacturing bricks, blocks, tiles etc.

SPECIFICATION FOR COMPRESSIVE STRENGTH CLASSIFICATION OF BUILDING BRICK (IS: 1077)

noreply@blogger.com (Rizwan Ahmad) — Mon, 28 Aug 2017 20:47:00 +0000

COMPRESSIVE STRENGTH CLASSIFICATION OF BUILDING BRICK

According to the Bureau of Indian Standard the brick are classified on the basis of compressive strength.

IS CLASSIFICATION (IS-1077)

class average compressive strength not less than(N/mm2)

1) 3.5 3.5

2) 5 5

3) 7.5 7.5

4) 10 10

5) 12.5 12.5

6) 15 15

7) 17.5 17.5

8) 20 20

9) 25 25

10) 30 30

11) 35 35

burnt clay brick having compressive strength more than 40.0 N/mm2 are known as heavy duty bricks and are used for heavy duty structures such as bridge, foundation, industrial building, multistory buildings, etc. the water absorption of these bricks are limited to 5% of it dry weight.

each class of brick as specified above are further divided into subclasses A and B based on tolerance and shape. subclass A bricks should have smooth rectangular shapes with sharp corners and uniform colour. subclass B bricks may have slightly distorted and round edges.

Subclass A Brick

dimension tolerance

(cm) (mm)

length- 380 12 mm ( less or more)

width- 180 6 mm (less or more)

height- 1) 9 cm 180 6 mm (less or more)

2) 4 cm 80 3 mm (less or more)

Subclass B Brick

Dimension Tolerance

(cm) (mm)

Length 380 30 (less or more)

Width 180 15 (less or more)

Height- 1) 9 cm 180 15 ( less or more)

2) 4 cm 80 6 (less or more)

Megastructure Art- The Home Of Civil Engineering

CONCRETE MIX DESIGN M30 GRADE IS-10262-2009

3. Target Mean Strength

4. Selection of water cement ratio

5. Selection Of Water Content

6. Cement Content Calculation

7. Calculation of sand and coarse aggregate

8. Estimation of the mix ingredients

CONCRETE MIX DESIGN M40 GRADE

DIFFERENT METHOD OF MIX DESIGN OF CONCRETE PROCEDURE

TYPES OF LOAD ACTING ON BUILDING (IS : 875)

HOW TO PERFORM COMPRESSIVE STRENGTH TEST OF CEMENT(IS:4031-PART 6-1988) ?

OBJECTIVE

APPARATUS

PROCEDURE

CALCULATION

STANDARD SPECIFICATION

HOW TO CHECK SOUNDNESS OF CEMENT BY LEE-CHATELIERS MATHOD (IS:4031-(PART 3)-1988) ?

OBJECTIVE

APPARATUS

PROCEDURE

CALCULATION

PRECAUTIONS

STANDARD SPECIFICATIONS

GENERAL GUIDLINES FOR REINFORCEMENT BAR

REINFORCEMENT BAR DETAIL GUIDELINE

TYPES OF REINFORCEMENT

INITIAL AND FINAL SETTING TIME OF CEMENT TEST (IS: 4031-(PART-5)-1988)

INITIAL AND FINAL SETTING TIME CEMENT TEST

Factors Affecting Initial And Final Setting Time Of Cement :

OBJECTIVE

APPARATUS

SAMPLE/SPECIMEN

PROCEDURE FOR INITIAL SETTING TIME

FINENESS TEST OF CEMENT (IS:4031-1996)

Sieve Analysis Method

Objective

Apparatus

Sample/Specimen

Procedure

Result

Air Permeability Method

The specific surface should not be less then following limits :

The Sedimentation Method

DESIGN OF SLAB (IS:456-:2000)

STEPS FOR DESIGN OF SLABS

Effective Span

Thickness of Slab

Reinforcement

d) Clear Cover

Steps In Design Of Slab :

IS SPECIFICATION FOR RCC SLAB DESIGN

RCC SLAB DESIGN SPECIFICATION :

1. Effective Span Of a Slab :

2. Depth Of Slab:

for one way simply supported slab :

for one way continuous slab (both end cont.)

For one way continuous slab (one end cont.) Effective depth d= Span /26 x modification factor).

For cantilever slab :

3. Load On Slab:

4. Reinforcement For Slab As Per IS 456: 2000

HOW TO PERFORM CONSISTENCY TEST OF CEMENT ?

FACTOR AFFECTING FINENESS OF CEMENT

TEST IMPORTANCE

TEST PROCEDURE

Objective

Apparatus

Sample/Specimen

Procedure

Result

MANUFACTURING OF ORDINARY PORTLAND CEMENT

RAW MATERIALS

Composition Of Raw Materials :

MANUFACTURING PROCESSES OF CEMENT (OPC)

These two processes differ in operation but fundamentals of both these processes are same.

DRY PROCESS

Steps involve in manufacturing of portland cement by dry method :

WET PROCESS

Step involve in the manufacturing of portland cement by wet process are :

SPLITTING TENSILE STRENGTH TEST OF CONCRETE (IS: 516)

For one way continuous slab (one end cont.)

Effective depth d= Span /26 x modification factor).