Quantification the effect of microsand on the compressive, tensile, flexural strengths, and modulus of elasticity of normal strength concrete

The objective of this study is to identify and quantify the effect of microsand content (MS) or silica fume (SF), water-cement-ratio (w/c) and curing time (t) on the compressive and tensile strengths of concrete at different strength ranges varied from 4 MPa to 55 MPa. In this study, over 1000 data were used to characterise the compressive and tensile strength behaviour. The range of w/c for modified concrete with different percentages of microsand up to 40% (by dry weight of cement) was in the range of 0.17% to 0.80%, compressive and tensile strengths were in the range of 4-55 MPa, and 1-7 MPa, respectively. Vipulanandan model correlated the relationship between mechanical properties of concrete modified with MS with a varied range of w/c and curing time, and the results were compared with the Hoek-Brown correlation model used in the literature. Based on the NLM parameters, the effect of MS was less than w/c and curing time on the compressive strength of modified concrete with MS in different strength range up to 55 MPa.