MIX DESIGN OF CONCRETE

Submitted by:

GAGAN ARORA (2002334) GAURAV BARGALI (2002335)

MANISH SHARMA (2002351) NISHANT SHARMA

(2002361) ANUBHAV GARG (2003428)

Under the Guidance ofAsst. Prof. Vikash Khatri

INTRODUCTIONMix design is a process of specifying the

mixture of ingredients required to meet anticipated properties of fresh and hardened concrete.

ORThe 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.

CONSTITUENTS OF cement CONCRETE

CementWater Fine Agg.Coarse Agg.Admixtures

GRADESNominal Mix (cement : fine aggregate : coarse aggregate)M5 1:5:10 M7.5 1:4:8M10 1:3:6M15 1:2:4M20 1:1.5:3

Design Mix (cement : fine aggregate : coarse aggregate)M25 and above

TESTINGTests on Coarse Aggregates The various tests carried out on coarse aggregates include the following:1) Aggregate Crushing Value test.2) Aggregate Impact Value test.3) Aggregate Abrasion Value test.4) Test for Determination of Flakiness Index.5) Test for Determination of Elongation Index. 

 

Tests on Cement The various tests carried out on cement include the following: 1) Standard Consistency test 2) Initial Setting time test 3) Final Setting time test 4) Soundness Test 5) Fineness Test

Aggregate Crushing Value testThe “aggregate crushing value” gives a relative measure of the resistance of an aggregate to crushing under a gradually applied compressive load.

weight of surface dry sample taken

in mould (W1 )2.5 kg

weight of fraction passing 2.36 mm

sieve (W2)0.28kg

Aggregate crushing value =

(W2/W1) * 10011.2%

Aggregate Impact Value testThe aggregate impact value gives relative measure of the resistance of an aggregate to sudden shock or impact.

Weight of sample (W1)

2.5 kg

Weight of fraction passing 2.36 mm I.S. Sieve (W2)

0.28kg

Aggregate impact value

(W2/ W1) * 100

11.2%

Aggregate Abrasion Value testThis test helps to determine the abrasion value of coarse aggregates as per IS: 2386 (Part IV)– 1963 .The apparatus used in this test are Los Angles abrasion testing machineWeight of aggregate

(W1)5kg

Weight of aggregate of retained from 1.7mm

sieve (W2)

1.29kg

Abrassion value= (W2/ W1)*100

25.8%

No. of charge 11Grade B

Test for Determination of Flakiness Index The flakiness index of aggregate is the percentage by weight of particles in it whose least dimension is less than three-fifth of their mean dimension. The test is not applicable to sizes smaller than 6.3 mm. This test is conducted by using a metal thickness gauge Range 16 – 20 mm

No. of aggregates 200Total wt. of aggregates (W1) 0.66 kg

Total wt. of aggregates passed (W2)

0.09 kg

Flakiness index= (W2/W1) *

10013.63 %

Test for Determination of Elongation Index

The elongation index of an aggregate is the percentage by weight of particles whose greatest dimension is greater than 1.8 times their mean dimension. This test is conducted by using metal length gauge.Range 10 – 12.5 mm

No. of aggregates 200Total wt. of aggregates (W1) 0.66 kg

Total wt. of aggregates passed (W2)

0.10 kg

Elongation index= (W2/W1) * 100

15 %

Various Tests done on Cement

Standard Consistency testThe basic aim is to find out the water content required to produce a cement paste of standard consistency as specified by the IS: 4031 (Part 4) – 1988. The principle is that standard consistency of cement is that consistency at which the Vicat plunger penetrates to a point 5-7mm from the bottom of Vicat mould.

Trial no. Wt. of cement(gm)

Water (gm)

Water (%)

Needle penetration

1 400 120 30 72 400 132 33 6

Standard Consistency = (132*100)/400 = 33%

Initial and Final Setting Time TestVicat apparatus conforming to IS: 5513 – 1976

Soundness Test of CementSoundness of cement is determined by Le-Chatelier method as per IS: 4031 (Part 3) – 1988.Apparatus – The apparatus for conducting the Le-Chatelier test should conform to IS: 5514 – 1969.Balance, whose permissible variation at a load of 1000g should be +1.0g and Water bath.

D2 – D1 = 1mm

Fineness test of CementSo we need to determine the fineness of cement by dry sieving as per IS: 4031 (Part 1) – 1996.The principle of this is that we determine the proportion of cement whose grain size is larger then specified mesh size.The apparatus used are 90µm IS Sieve

wt. of Cement sample(W1)

100gms

wt. of Residue(W2) 2.5gms

% wt. of residue(W2 /W1)

2.5%

WORK TO BE DONE:Compressive Test on CementTests on SandFineness Modulus on Aggregate Mixing and Casting of Concrete cubes:

>With Different W/C Ratio>By Adding Different Admixtures

Determination of Compressive Strength of Concrete Cubes at : 3,7,28 Days

Rate Analysis  

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