Use of non-potable water sources in pavement construction: A review

The potential for a global water crisis looms in the face of declining precipitation and growing population. Immediate action is required to address the issue of water shortage. Water recycling and reuse of treated wastewater (TWW) in practical applications holds the potential to facilitate this problem. TWW refers to the wastewater being treated at a sewage treatment plant to meet the required safety standards. One such application of TWW is using it as a replacement for potable water in road construction. A typical road construction requires huge amount of water for various purposes, such as soil compaction, dust control operations, concrete production, curing, etc. The primary focus of this review is to highlight the feasibility of using alternative water sources in road construction activities. The effect of water treatment level on pavement material properties has been reviewed. Further, the influence of toxic chemical compounds present in TWW on the fresh and hardened properties of concrete is thoroughly discussed. The fundamental reasons behind the change in mechanical properties of subgrade and granular layers with the application of TWW are highlighted. Additionally, data on the chemical characteristics of non-potable water and their effect on pavement durability are surveyed and summarized. The review indicates that there is a need to explore the use of TWW in subgrade and granular layers. Further, the effect of source and treatment level on the mechanical properties of different pavement layers should be investigated with more rigor. Life cycle assessment (LCA) and field evaluation of pavements constructed using different sources of TWW will build more confidence in its use as a sustainable construction material.