SUBMITTED BY : SHIV KUMAR SINGH

UNIVERSITY ROLL NO: 100870102588

CGC GHARUAN MOHALI

B.TECH CIVIL

GUIDE BY- ER. RAMANDEEP

Ø AIM OF PROJECT : TO STUDY THE EFFECT OF FLYASH(CEMENT REPLACEMENT) ON CHARACTERSTIC STRENGTH OF CONCRETE.

MATERIAL USED:

Cement(Opc 43 Grade), Fine Aggregates, Coarse Aggregates(20mm), Fly Ash

Equipments Used: Concrete Moulds, Mechanical Vibrators, Tamping Rod, Trowel, Shovel.

PHYSICAL PROPERTIES OF PORTLAND CEMENT

1.FINENESS: it is the measure of size of particles and it is expressed in terms of specific surface of cement.as per is specifications ,the residue of cement should not exceed 10 % when seived on 90 micron sieve.it can be calculated from particle size distribution or by permeability.in addition the amount of water required for constant concrete decreases.

2. SOUNDNESS OF CEMENT: the unsoundness of cement is caused by undesirable expansion of some of its constituents ,sometimes after setting. The large change in volume accompanying expansion results in disintegration and severe cracing . The unsoundness is due to presence of free lime and magnesia in the cement . The free lime hydrates very slowly because it is covered by thin film of cement

Which prevents direct contact between lime and water.after the setting of cement the moisture presence into thre few time reacting in the hydration since slaked time occupy a large volume the expansion take place resulting in severe cracking.the unsoundness due the presence of magnesia is similar to that of time. The unsoundness may be reduced by ,

Limiting the mgo content to less than 0.5%

Fine grinding

Thorough mixing

GENERAL –PURPOSE PORTLAND CEMENT

The commonly used portland cement in india is branched as 33 grade (is 269-1989) , 43 grade (is :8112-1989) and 53 grade (is 12269-1987) having 8 days mean comp. Strength exceeding 33 mpa , 43 mpa and 53 mparespectively.the conventional opc that is 33 grade cement has virtually disappeard and has been displaced by high rate 43 grade cement . The comp. Strength of 43 grade cement are 23 and 33 mpa at the end of 3 and 7 days resp. The use of cement was originally resticted to production of railway sleepers and generally refered to as sleeper cement. The railway specification that the initail setting time should not be less than 90 nmin. At higher water cement ratio the concete produced with high strenght cement has about 80%higher strength at w/c ratio it has 40% higher strength than that of concrete using 33 grade opc. The cost of high strength is only imaginary higher than the opc . The use of this cement in the usual 1:2:4 nominal mix with a water cement ratio of 0.60-0.65 can easily yeild m25 concrete. Its composition and properties are goverened by is 8112 -1989. Grater fineness of 43 and 53 grade cement inc. Workability due to reduction of frictioin between aggegate.is 10262:1982 has classified the opc grade wise from a to f depending upon 28 days comp. Stength as a( 3 to 0.5-37.5 mpa ) ,b (37.2-42.5) ,c 42.5-47.5 , d (47.5-52.5), e (52-57.5), f (57.5 -62.5).

All though cement of grades of 43 and 53 are desireable for economic design of high grade concretes however to make high strength concrete a high performance concrete will require extremely careful batching , mixing , transportation, placing, compaction and curing

OPC BASED CEMENT

The cement is similar to opc but with higher c2s content and fine grinding . Ahigher fineness of cement particle provide gratersa not les 325000mm*2/gram for action with water . It gain strength more quickly than opc though the final strength is finally higher the one day strength is equal to 3 days strength of 33 grade opc with the same water cement ratio.the cement is used where a rapid strength development is required....

The rapid gain of strength is accompanied by a higher rate of heat development during the hydration of cement.This may have advantage of in cold weather concreting, but a higher concrete temperature may lead to cracking due to thermal contraction and therefore should not be used in mass concreting or thick structural sections.

LOAD V/S STRENGTH TABLE

REPLACEMENT OF CEMENT

LOAD IN KN

AREA

COMPRESSIVE STRENGTH

0 %

312 KN

150*150 MM

13.4 N/sq.mm

15%

270 KN

150*150 MM

12 N/sq.mm

35%

160 KN

150*150 MM

7 N/sq.mm

The mix design has been prepared as according to is : 10262-2009 and are as below :

CONCRETE MIX DESIGN :-

M25 was designed using the is code design method procedure and details of mix design are

Design for m25 mix as per is :10262-2009

Characterstic compressive strength = 25 n/mm2

Degree of quantity control = good

Type of exposure = mild

Degree of workability = high

Slump= 60-180mm

Vee-bee = 0-3 sec

Type of cement= opc

Maximum aggregate= size= 20mm

Specific gravity of cement = 3.38

Specific graviity of fine aggregates =2.65

F.m of fine aggregate =2.50

Grading zone of fine aggregate = zone iii

As per is :383-1970

TARGET MEAN STRENGTH

the target mean stength is determined by using the relation ft =fck +ks where fck is a characterstic comp. strength at 28 days and s is standard deviation and k is standard coefficient for the defination of charactersticstrengthgiven in is 456-2000 that

k=1.65

s=5.34 for m25 mix and good degree of control

ft = 25=1.65 x 5.3

ft= 33.75 n/mm2

SELECTION OF WATER CEMENT RATIO:-

The water cement ratio for target mean strength is chosen as 0.45

Selection of water and sand content

From table 2 10262-2009 , maximum water content for 20 mm aggregate =180l sand content as % of taotal aggregate by absolute volume for water cement 0.42=35% . Therefore applying correction by is 10262-2009 according to which( aggregate cement should be decreased at the o.01 for every 0.05 increase in water cement ratio

The respectively kg before sand content to be 32%

Cement content

W/c ratio =0.45

Water content= 186 kg /cu-m

Cement content= 186/0.45=413.33kg/ cu-m

Determination of proportion of fine and coarse aggregate

For 20mm nominal size aggregate ,entrapped air is 2%

Fine aggregate ,

v = (w+c/sc+<1/(p x fa/sfa>))/1000

Where v = absolute vol. Of fresh concrete = gross volume (i m3) minus the volume of entaped air

Sc= specific gravity of cement

W= mass of water

C= mass of cement

P= ratio of fine aggregate to total aggregare by absolute volume

Fa= total mass of fine aggregate

Sfa= specific gravity of standard surface dry fine aggregate

0.98= (186+413.33/3.12+<(1/0.3 x fa/254)>)x 1/1000

On solving the above equation we get

Fa=537.83 kg cub-m

Coarse aggregates

v = (w+c/sc+<1/(p x ca/sfa>))/1000

Where ca= total mass of coarse aggregate

sa= sp. Gravity of std. Coarse dry aggregate

ca= 1202.78 kg/cu-m

MIX DESIGN PROPORTION ( 0.45)

Cement(kg/cu-m)

Sand (kg/cu-m)

Coarse aggregate ( kg/cu-m)

413.33

537.8

1202.78

1

1.3

2.9

Development of mix proportioning procedurefor flyash concrete

Abstract :-

Presently, no mix proportioning procedure is available for the flyash concrete for the typicalIndian concrete-making materials and mix proportioning of flyash concrete is generally carried out bytrial and error. An R&D project has been taken up by Authors\\\\\\\' organization to develop a dependablemix proportioning procedure for such concretes.

The experimental work was carried out with two samples of ordinary Portland cement havingdifferent strength levels. Relationships have been developed between water/cementitious materialsratios and 28 days compressive strengths of concrete for different flyash contents in the mixes.

Taking relationship between water/cementitious materials ratio and strength of concrete as astarting point of the procedure, the remaining steps of the mix design procedure have been finalized.

The experiments are being further conducted with cement samples having different strengths and withmore flyash samples. The procedure is also being tried for proportioning of flyash mixes forcommercial concretes being supplied by an RMC plant in India to various construction sites.

Flyash, which is produced by thermal power plants in large quantity as a waste material (about 90 million tonnes annually), is used as a mineral admixture in concrete to improve its strength and durability characteristics.Presently, good quality of fly ash conforming to IS 3812is available in most of the modern thermal plants in India. In many Countries like USA, UK, Netherlands, Germany etc. flyash is being used as mineral admixture for making good quality and durable concretes

Flyash is used in concrete not only for normal building constructions, but also in high strength concretes for special structures like long span bridges, high rise structures, tunnels to achieve durability in concrete and to avoid formation of microcrakes caused by excessive heat of hydration produced due to large quantity of high grade cement required to be used for making high strength concrete. In the fourth revision recently, IS:456-2000 the code of practice for plain and reinforcedconcrete has also included the use of flyash in concrete as part replacement of ordinary Portland cement provided uniform blending with cement is ensured.

Need for Mix Proportioning Procedure for Flyash Concrete

The Indian Code, IS 10262 recommended a mix design procedure for concrete without chemical and mineral admixtures However, no mix proportioning procedure is available for the flyash concrete for the typical Indian concrete-making materials and mix proportioning of flyash concrete is generally carried out by trial and error. Extensive research has been carried out to arrive at a proper method of proportioning the flyash concrete mixes and to study the effect of flyash addition on the properties of concrete. According to Smith the water cement ratio for flyash concrete was calculated on the basis of the \\\\\\\'Cementing efficiency factor\\\\\\\' for flyash. This factor depends on the curing period, strength of the mix and the type of flyash. Cannonsuggested that the difference in the yield due to a lager volume of cementitious material in the flyash mix should be balanced by reduction in sand content. Adoption of this procedure changes the gradation of the original mix. The demand for water in such mixes depended on the mix itself, increased in certain cases and decreased in others. Lovewelland Washafound that the flyash addition had to exceed the amount of cement removed in order to achieve the same strength. Additional quantity of flyash needed depended on the strength of the mix. Ghoshprepared design charts suitable for design of flyash concrete. He found that the constants in Abrams\\\\\\\' equation changed with the ratio of flyash and cement. However, these equations are not quantified. The design charts were prepared for various flyash contents and water cementitious ratios. Many other researches have carried out studies for developing a mixdesign procedure for flyash concrete but still a need has been felt to develop a dependable mix design procedure for such concretes. Building research establishment gives procedure for designing flyash mixes with the available quality of materials i.e. cement and flyash. This procedure provides for estimation of w/c ratio corresponding to the target strength of concrete based on cementing efficiency factor. However, it is not directly applicable for concrete mixes made with materials used in India.

Ø Experimental Work done

Materials used :-

Two types of ordinary Portland cement (OPC) i.e.

1. 43 grade OPC

2. 53 grade OPC

Conforming to IS:8112grade OPC conforming to IS: 12269are used and their physical and chemical characteristics are Crushed quartzite was used as coarse aggregate and the a pit sand known as\\\\\\\'Badarpur\\\\\\\' sand conforming to grading zone II requirement as per IS 383-1970 was used as fine aggregate. The flyash sample collected from Talchar super thermal power station was used for thestudies. The flyash sample conformed to the requirement of IS 3812

Characteristics of Flyash sample

Characterstics

Result

Silica, Si02,%

60

Loss on Ignition%

0.3

Lime Reactivity

7.2

Fineness