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PROJECT REPORT
NAME OF PROJECT: EFFECT OF FLYASH (CEMENT REPLACEMENT) ON CHARACTERSTIC STRENGTH OF CONCRETE
SUBMITTED BY : UDAY INDU SHARMA
UNIVERSITY ROLL NO: 100870102599
CGC GHARUAN MOHALI
B.TECH CIVIL
PROJECT INCHARGE: ER. RAMANDEEP DHILLON
NAME OF STUDENTS :---( GROUP MEMBERS)
UDAY INDU SHARMA (100870102599)
SHIV KUMAR SINGH (100870102588)
SHUBHAM CHAUHAN (100870102591)
SHREYAK SHARMA (100870102590)
NAVODIT MEHRA (100870102557)
SAWAN MAHAJAN (100870102586)
SANDEEP SHARMA (100870102582)
SOURAV GUPTA (100870102593)
AMIT RANA (100870102499) .
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 mpa respectively.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 . A higher fineness of cement particle provide grater sa 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
REPLACEMENT LOAD AREA(mm) COMPRESSIVE STRENGTH
O% 312 KN 150*150 13.4N/SQ. M
15% 270 KN 150*150 12N/SQ. M
35% 160 KN 150*150 7 .04 N/SQ. M
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/SQ. M
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 characterstic strengthgiven 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 OFWATER 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 procedure for flyash concrete
Abstract :- Presently, 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. 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 having different strength levels. Relationships have been developed between water/cementitious materials ratios 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 a starting 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 with more 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. Cannon suggested 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. Lovewell and Washa found 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.
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:8112 grade OPC conforming to IS: 12269 are 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 338
The following steps were taken during the execution of the project :-
1. OPC 43 grade cement of Ultra Tech quality was used in the project
2. Sand after sieving was used as fine aggregate
3. Final mix of 1: 1.5:3 was adopted for successful casting of moulds
4. Oiling was done before placing of concrete inside the moulds
5. Proper compaction by tamping rods (min. 25 blows) was given
6. The concrete was filled in 3 layers after giving 25 blows in each layer
7. Top surface was finalized to give a good appearance and for getting proper shape
8. The replacement by weight was 0 , 15, 35 %
9. Two cubes each of 0 , 15, 35 were used
10. Moulds were removed after 24 hours of setting
11. The curing for 7 days was done
12. After 7 days of successful curing the cubes were taken in the lab
13. The cubes were placed inside the compression testing machine and the different loading conditions were applied on it
14. The load was divided by the area to give the subsequent results
15. The final computations were done Stress = Load / Area
16. After calculating the stress results were plotted in a tabular form
17. The decrease in the compressive strength was noticed as was the aim of the project
FINAL METHODOLOGY :- The proposed method for mix proportioning of flyash concrete is based on the design curve of free water/cementitious materials ratio vs 28 days compressive strength of concrete for specified flyash content and 28 day strength of cement. The main steps of the proposed procedure are as follows:
1) Determination of free water/cementitious material ratio. For a given target strength and percentage of flyash, determine the corresponding water/cementitious materials ratio from depending upon the 28 day compressive strength of cement.
2) Determination of water and fine aggregate contents. Based on the maximum size and type of coarse aggregate to be used and the required level of workability, determine the water and fine aggregate contents.
3) Determination of cement and flyash contents Combining the results of step 1 and 2, determine the cement and flyash contents.
4) Determination of coarse and fine aggregate contents. Determine the coarse and fine aggregate content by absolute volume method or any other suitable method. The procedure given in IS 10262 can be adopted
CONCLUSIONS OF THE PROJECT..
After successful completion of the project we found out that the characterstic compressive strength of concrete decreases as we keep on increasing the content of flyash(cement replacement).hence flyash should be used in least quantity moreover flyash based cements are used now a days which contain a limited quantity of flyash in it…
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