Model Technics to Predict the Impact of the Particle Size Distribution (PSD) of the Sand on the Mechanical Properties of the Cement Mortar Modified with Fly Ash

Abstract

Despite many of the research studies on the effect of the particle size distribution of the sand and fly ash content on the mechanical behavior of the cement mortar, there has not been a comprehensive study investigating the effect of particle size distribution curve corresponding to 10% of finer (d10), fly ash content, curing time, sand particle size distribution properties (d10), and water to cement ratio (w/c) on the compressive (σc), tensile (σt), and flexural (σf) strengths of cement mortar. Therefore, this study investigates the subject which could be beneficial for the geotechnical and building and construction field. In this study, more than 1000 data on the mechanical properties of the cement mortar modified with different percentages of fly ash varied from 5 to 75% (by dry weight of the cement) collected from the literature. Statistical analysis and modeling were performed on the collected data. Vipulanandan p-q model was used and compared to the Logistic Growth model to predict the particle size distribution of sands used in the cement mortar. The water to cement ratio (w/c) of the cement mortar ranged between 0.20–0.80 percent and the compressive strength (σc), tensile strength (σt) and flexural strength (σf) of cement mortar modified with fly ash up to 90 days of curing were ranged between 15–88 MPa, 0.4–5 MPa, and 1–10 MPa, respectively. Vipulanandan correlation model was also used and compared with the Hoek–Brown model to correlate the mechanical properties of cement mortar modified with fly ash. The analysis and modeling results of the present study showed that there is a good relationship between the compressive strength (σc) with w/c, curing time, fly ash content and d10. Based on the coefficient of determination (R2) and root mean square error (RMSE) the compressive strength (σc), flexural strength (σf) and tensile strength (σt) of cement mortar quantified well as a function of w/c, the percentage of fly ash, curing time, and d10 using nonlinear relationship.