Locally Sourced Coarse Aggregate Effect on the Compressive Strength of Concrete: Case Study of Anambra State Sandstone

Abstract

This paper examines the coarse aggregate effect of Anambra State
sandstone on the compressive strength of concrete using response surface
methodology. This has become imperative due to its abundant availability
in the south east region of Nigeria. Regression equations relating the
compressive strength of the sandstone and granite concrete with both the
curing duration, fine aggregate, cement and water/cement ratios were
developed. The suitability of these equations was tested using the analysis
of variance (ANOVA).The results show that the maximum compressive
strength of the granite and sandstone concrete were 36.25 N/mm2 and
35.0 N/mm2 at 28 days of curing using 0.48 w/c ratio, This was only a
1.04% increase of compressive strength of the granite concrete over the
sandstone concrete. The ANOVA for the quadratic model shows the
adjusted R2 of 0.9860 and a linear model for the sandstone shows the
adjusted R2 of 0.9084. This shows that quadratic model for the granite
concrete and linear model for the sandstone can predict the compressive
strength of the respective concrete. Therefore, Anambra State sandstone
can be used for heavy structural works.