Abstract:
Compressive strength is an important topic for concrete. This paper discusses the use of
admixture on concrete to increase compressive strength and also the economical effect
of using admixture on concrete. In our project, normal concrete and concrete with
admixture cylinders are prepared and tested for compressive strength at the end of 7, 14,
and 28 days of curing. The results are compared for both types of concrete.
The main purpose of this research is to investigate the compressive strength of normal
concrete and concrete with admixture. In this thesis project, we prepared a total of 36
cylindrical samples in four different sets, and in each set, there are nine samples. Doing
this project work we maintained as per ASTM standards guideline. We are following
the standard grade of concrete M20 and the mix ratio was 1:1.5:3. In all of the samples,
we used the same amount of cement, coarse aggregate, fine aggregate, and as well as
water/cement ratio. Among this one set we prepare without admixture and rest of the
three we used admixture in three different percentages these are 4.5 ml, 6.7 ml, and 8.9
ml per sample. After three periods of curing 7, 14, and 28 days we tested compressive
strength. After 28 days the results was 3218 psi (without admixture), 3356 psi (using 4.5
ml admixture), 3559 psi (using 6.7 ml admixture), and 3786 psi (using 8.9 ml admixture)
and additionally cost increase 1.20 tk. (using 4.5 ml admixture), 1.70 tk. (using 6.7 ml
admixture), and 2.30 tk. (using 8.9 ml admixture) per sample. Comparing all of results
we can say that using 6.7 ml admixture is suitable percentages comparing to economical
effect and strength.
All the Codes and conducts has been maintained according to ASTM standard
specifications during the thesis work.
