Impact of treated wash water from ready mix concrete plants on concrete properties and durability

Abstract

Concrete production consumes nearly 16% of global freshwater resources, highlighting the urgent need for sustainable alternatives to potable water. This study investigates the feasibility of using treated wash water from ready-mix concrete plants as a partial or full replacement for mixing water. Concrete mixes were prepared with 25%, 50%, 75%, and 100% wash water replacement ratios to evaluate the impacts on fresh and hardened properties as well as durability. Electrical resistivity testing was integrated into the experimental programme to assess the durability performance of concrete containing varying wash water contents. The results showed a reduction in workability of up to 50% compared to the control mix prepared with potable water. At 28 days, compressive strength decreased by 15.9%, 17.3%, and 18.3% for mixes containing 25%, 75%, and 100% wash water replacement, respectively. Electrical resistivity increased significantly with higher wash water replacement by 44% and 60% for mixes with 25% and 50% wash water replacement, and by up to six times at full replacement, indicating enhanced durability and resistance to corrosion. Furthermore, empirical equations were developed and validated against the experimental data to estimate the reduction in compressive strength of concrete mixes incorporating treated water. These findings provide performance-based guidance for the broader adoption of treated wash water as a sustainable alternative in concrete production while maintaining acceptable structural and durability performance.