Project on Concrete Mix Design for various grades of Concrete
Aim : Calculate the concrete mix design for M35 grade concrete with flyash & M50 grade concrete without Fly ash.
Procedure :
1. Calculate the concrete mix design for M50 grade concrete without fly ash.
Data given :
a. Grade of concrete : M50
b. Cement type : OPC 43
c. chemical admixture : superplasticizer
d. Fine aggregate : zone II
Specific Gravity
a. Cement = 3.15
b. Coarse aggregate (20mm) = 2.65
c. Fine aggregate : 2.61
d. Cement : 400 Kg (assumed)
e. Maximum water cement ratio : 0.45
Calculations
a. Target Mean strength (F'ck = fck + 1.65S) = 50+(5x1.65) = 58.25 Mpa
b. Water Cement ratio = 0.35
c. Approximate water content for 20mm maximum size of aggreagte = 180 kg/m^3 (As per Table no. 5, IS : 10262). As plasticizer is proposed we can reduce water content by 20%
Wter content = 180 x 0.8 = 144kg/m^3
Calculation of cement content
a. water cement ratio = 0.35
b. water content per cum of concrete = 144kg
c. cement content = 144/0.35 = 411.4kg/m^3
d. cement content = 412 kg/m^3(As per contract minimum cement content 400kg/m^3) hence, ok
Calculations of CA & FA
a. Volume of concrete= 1m^3
b. Volume of cement = (412/3.15) X (1/1000) = 0.13076m^3
c. Volume of Water = (144/1) X (1/1000) = 0.144m^3
d. Volume of admixture = (4.994/1.145) X (1/1000) = 0.0043m^3
e. Total weight of other materials except coarse aggregate = 0.1308 + 0.144 + 0.0043 = 0.2791m^3
f. Volume of coarse & Fine aggreagte = 1-0.2791 = 0.7209m^3
g. Volume of F.A. 0.7209 X 0.33 = 0.2379m^3 (Assumin 33% by volume of total aggreagate)
h. Volume of C.A. = 0.7209 - 0.2379 = 0.4830m^3
Therefore weight of F.A. = 0.2379 X 2.61 X 1000 = 620.919 KG/m^3
Weight of F.A. = 621 Kg/m^3
Therefore weight of C.A. = 0.4830 X 2.655 X 1000 = 1282.365 Kg/m^3
Weight of C.A. = 1284 kg/m^3
Cement = 412 X 1.025 = 422 kg
Water = 144 X 1.025 = 147.6 kg
Fine Aggregate = 621 kg
Coarse aggregate = 706 kg
Admixture is 1.2% by weight of cement = 5.064 kg
Cement:F.A:C.A ratio = 1:1.1472:3.043
Conclusion :
Cement Fine aggreagate and coarse aggreagate ratrio is = 1:1.1472:3.043