Valorization of waste pond ash in cement mortars and prediction of mechanical properties by simple linear regression

Pond ash disposal in open fields is a major environmental concern due to huge land requirements. One of the approaches to utilizing pond ash is by replacing it with river sand in cement mortars. Hence, in the current study, pond ash was used to replace river sand up to 100% by volume. The present study evaluates the mechanical properties using volumetric mix proportions of 1:4 and 1:5 (cement: sand). The pozzolanic activity of pond ash through the strength activity index (SAI) and Frattini test was also evaluated. The compressive strength of the 1:4 mix with 30% pond ash increased by 26% compared to the control mix. Drying shrinkage was found to increase by 35-40% in both mix proportions. Microstructural studies were conducted to support the mechanical properties of mortar results. Linear regression models were also developed using experimental data to establish the relationship between mechanical properties. Incorporating up to 50% pond ash in cement mortars increased the mechanical properties of mortars, except for drying shrinkage. Thus, waste pond ash can be valorized as fine aggregate in cement mortars. This study will have direct field application by replacing river sand with up to 60% pond ash, reducing mortars' environmental burden and cost.