Mechanical and Durability Properties of High Strength Mortar with Construction Waste and Recycled Wastewater

Abstract

This study explores the combined use of two industrial by-products, Concrete Waste (CW) and Recycled Water (RW) as sustainable alternatives in High-Strength Mortar (HSM). The goal of this study is to reduce the environmental impact of cement production and sand extraction in the construction industry. We addressed the research gap by testing seven mixtures with 100% RW and varying amounts of CW as a replacement for cement or sand. We evaluated mechanical and durability properties using standardized tests for compressive strength (ASTM C 109), sorptivity (ASTM C1585), and drying shrinkage (ASTM C596). The results showed that using 100% RW is a practical option, with the control mix achieving 91.3 MPa. The replacement strategies were important, such as- substituting cement with CW led to a decrease in compressive strength (down to 60.3 MPa) and reduced durability. On the other hand, replacing sand with CW produced excellent results. The 40SRW mix, which replaced 40% of the sand, maintained compressive strength at 91.7 MPa and sorptivity at 0.0036 /√s, similar to the control mix. It also shows better dimensional stability, reducing drying shrinkage by 15.6%. The study concludes that the 40SRW formulation is an ideal sustainable mixture. It also supports a circular economy approach by delivering high mechanical performance and durability while maintaining structural integrity.