Project on Concrete Mix Design for various grades of Concrete

• i) the coarse aggregate should confirm of table 2 of IS 383
• Fine aggregate confirm grading zone 1 of table 4 IS 383
• target strength of mix concrete. Fc'k = fck+1.65S. = 35+1.65(5) = 43.25n/mm2
• Selection of water cement ratio from table 5 of IS 456:2000 for server exposure . max water cement ratio=0.45 Based on experience graph adopt water cement ratio as 0.43. 0.43<0.45 (hence ok)
• Selection of water content:. From table 2 of IS 10262:2009 max water content for 20mm aggregate= 186liters( for 25-50 slump). W= 186 liters. . . Estimate water for 100mm slump. 180+180*6/100=197liters. As superplasticizers add based on trails water content reduction of 29% achieve with plasticizer, hence water assumed water content w.c= 197- 197*29/100= 140liters
• Calculation of cement content. W/c = 0.43 , C= 140/0.43 = 326kg/m3. From table 5 of ISC456 2000 Min cement exposure condition=320kg/m3. Now 326kg/m3>320kg/m3. i) the percentage of flyash needs to be decided based on the requirements and quality of material. ii) increase in cementitious material Based on experience and trial ( the ex is with increase of 10% cementitious material content),. Cementitious material content=326*1.10 = 359, water content= 140liters, water cement ratio= 140/359=0.389. Flyash@30% of total cementitious material content=359*30%=108kg/m3. , Cement (opc)= 359-108= 251kg/m3. Saving with flyash=326-251=75kg/m3, flyash utilizes= 108kg/m3.
• Proportion of vol of coarse aggregate and fine aggregate from table 3 of IS 10262:2009 ,vol of coarse aggregate corresponding to 20mm size and fine aggregate (zone 1)for water cement ratio of 0.5=0.6, in place of w/c ratio is 0.43 ,so w/c ratio should be lower by 0.07 with increase in volume of coarse aggregate by 0.014 , the correct volume of coarse aggregate for the water cement ratio of 0.43 = 0.614, for pumpable concrete the values are reduced by 10%, therefore volume of coarse aggregate=0.614*0.9=0.55, vol of fine aggregate=1-0.55=0.45.
• Mix calculation per unit volume. a) vol of concrete= 1m3.
• b) vol of cement= mass of cement/sp gravity of cement *1/1000 =251/3.15 *1/1000 = 0.079m3.
• c)Vol of flyash=mass of flyash/sp.gravity of flyash *1/1000 =108/2.2*1/1000=0.049m3
• d) vol of water = mass of water/sp gravity of water*1/1000=140/1*1/1000=0.14m3
• e)vol of chemical admixture=mass of chemical admixture by specific gravity of admixture*1/1000= 7.6/1.145*1/1000=0.006m3
• f)vol of F.A and C A= (a-(b+c+d+e))=1-(0.079+0.049+0.14+0.006)=0.726m3.
• Mass of C A= f*vol of C.A*sp.gravity of C.A*1000)=0.726*0.55*2.74*1000=1094kg/m3
• Mass of F.A=f*vol of F.A*sp gravity of f.A*1000=0.726*0.45*2.74*1000=895kg/m3
• Cement =251kg/m3
• Flyash=108kg/m3
• Water=140kg/m3
• F.A= 895kg/m3
• C.A=1094kg/m3
• W.C=0.43
• Trial mix ratio=1:2.49:3.04.

Mix m50

1. i) the coarse aggregate should confirm of table 2 of IS 383
2. Fine aggregate confirm grading zone 1 of table 4 IS 383
3. target strength of mix concrete. Fc'k = fck+1.65S. = 50+1.65(5) = 58.25n/mm2
4. Selection of water cement ratio from table 5 of IS 456:2000 for server exposure . max water cement ratio=0.45
5. Selection of water content:. From table 2 of IS 10262:2009 max water content for 20mm aggregate= 186liters( for 25-50 slump). W= 186 liters. . . Estimate water for 100mm slump. 180+180*6/100=197liters. As superplasticizers add based on trails water content reduction of 20% achieve with plasticizer, hence water assumed water content w.c= 197- 197*29/100= 158liters
6. Calculation of cement content. W/c = 0.45 , C= 158/0.45= 351kg/m3. From table 5 of ISC456 2000 Min cement exposure condition=320kg/m3. Now 351kg/m3>320kg/m3.
7. Proportion of vol of coarse aggregate and fine aggregate from table 3 of IS 10262:2009 ,vol of coarse aggregate corresponding to 20mm size and fine aggregate (zone 1)for water cement ratio of 0.5=0.6, in place of w/c ratio is 0.45 ,so w/c ratio should be lower by 0.05 with increase in volume of coarse aggregate by 0.01 , the correct volume of coarse aggregate for the water cement ratio of 0.45 = 0.61, for pumpable concrete the values are reduced by 10%, therefore volume of coarse aggregate=0.61*0.9=0.549, vol of fine aggregate=1-0.549=0.451
8. Mix calculation per unit volume. a) vol of concrete= 1m3.
9. b) vol of cement= mass of cement/sp gravity of cement *1/1000 =351/3.15 *1/1000 = 0.117m3.
10. c) vol of water = mass of water/sp gravity of water*1/1000=158/1*1/1000=0.158m3
11. d)vol of chemical admixture=mass of chemical admixture by specific gravity of admixture*1/1000= 7.6/1.145*1/1000=0.006m3
12. f)vol of F.A and C A= (a-(b+c+d))=1-(0.1117+0.158+0.006)=0.7297m3.
13. Mass of C A= f*vol of C.A*sp.gravity of C.A*1000)=0.7297*0.549*2.74*1000=1098kg/m3
14. Mass of F.A=f*vol of F.A*sp gravity of f.A*1000=0.7297*0.45*2.74*1000=902kg/m3
15. Cement =351kg/m3
16. Water=158kg/m3
17. F.A= 902kg/m3
18. C.A=1098kg/m3
19. Chemical admixture=7kg/m3
20. W.C=0.45
21. Trial mix ratio=1:2.569:3.128