Application of industrial treated wastewater in rigid pavement construction: Advancing towards sustainable infrastructure

Abstract

Rigid pavement construction relies on freshwater for concrete production and subgrade compaction, contributing to the depletion of natural water resources. This highlights the urgent need for alternative water sources to reduce freshwater dependency in pavement construction. Thus, the current study investigates the use of paper and pulp industry treated secondary and tertiary wastewater in pavement quality concrete (PQC), dry lean concrete (DLC), and subgrade construction. The compaction characteristics and leaching potential of subgrade soil was assessed. Further, the mechanical and microstructural behavior of cement concrete were evaluated. Results indicated that treated wastewater marginally influenced the compaction properties of subgrade. Minerals in treated wastewater enhanced the CBR of subgrades, while metal concentrations remained within regulatory limits. The secondary treated wastewater (STWW) reduced the maximum dry density (MDD) of DLC approximately less than 5% and delayed ettringite formation in PQC. The study showed that treated wastewater from the paper and pulp industry can be a possible alternative for sustainable pavement construction practices.