Modeling and statistical assessments to evaluate the effects of fly ash and silica fume on the mechanical properties of concrete at different strength ranges

Abstract

This research aims at investigating the effect of adding Fly ash (FA) and Silica Fume (SF), water/cement ratio (w/c), and curing time (t) on the compressive strength (CS), flexural strength (FS) and tensile strength (TS) of normal strength concrete (NSC) high strength concrete (HSC) up to 90 days of curing. This research mainly aims to investigate the effect of adding Fly ash (FA) and Silica Fume (SF). Statistical analysis and modeling based on the collected data from different research studies were performed in this research. The w/c ratio for concrete, modified with fly ash (up to 80%) and the concrete modified with silica fume (up to 45%) was ranged between 0.19–0.87, 0.25–0.55, and 0.2–0.80, respectively. The compressive, flexural, and tensile strengths ranges for concrete were 10.5–81.9 MPa, 2.6–9.9 MPa, and 0.41–6.01 MPa, for concrete modified with FA were 13.8–79.9 MPa, 2.53–10.4 MPa, and 0.30–6.5 MPa and for concrete modified with SF were 2.9—99.3 MPa, 3.8–11.9 MPa, and 1.06 –6.6 MPa respectively. The compressive strength was correlated very well to the flexural and tensile strength. Based on the coefficient of determination (R2) and root mean square error (RMSE) the compressive strength, flexural strength, and tensile strength of concrete as a function of w/c ratio, FA content, SF content and curing time quantified very well using nonlinear (NLM) relationship. Based on the NLM parameters, the effect of FA and SF were less than w/c ratio and curing time on the mechanical strength of modified concrete in different strength ranges.