A Novel Approach to High-Volume Replacement of River Sand by Waste Pond Ash in Cement Mortar Using Multicriteria Models: Engineering Properties, Sustainability Aspects, and Cost

Abstract

In the current study, the high-volume replacement of river sand (20%, 30%, 40%, 50%, 60%, 80%, and 100%) by pond ash in cement mortar was considered using a 1∶3 volumetric mix proportion to evaluate the engineering properties, sustainability aspects, and cost of mortar mixes. The compressive strength, tensile bond strength, and adhesive strength increased by 30%, 21%, and 24%, respectively, at 30% replacement and were in line up to 60% replacement as compared with the reference mix. However, the drying shrinkage was observed to increase with volume replacement of river sand. The life-cycle assessment of mixes containing pond ash showed reductions in the environmental impacts. Four different scenarios were considered on the basis of the preference advantage of the indicators. Considering the engineering properties, sustainability aspects, and cost as the primary indicators, the gray clustering analysis showed that the mix with 60% volume replacement exhibited the best performance among the mixes under Scenario S-1, while TOPSIS and VIKOR showed that the mix with 50% volume replacement exhibited best performance under Scenario S-1. Overall, the comparison of all scenarios showed that the mix of 60% pond ash had the best performance followed by the mix with 50% pond ash, irrespective of the multicriteria decision-making techniques and preference advantages.