Comparative Experimental Investigation on Internal Curing Agents for Concrete Under Limited External Curing

Water scarcity is a critical challenge for the global construction industry, which accounts for approximately 15% of global freshwater consumption, with a substantial share attributed to concrete curing alone. Studies report that 1 m³ of concrete requires up to 3 m³ of water solely for curing. This study investigates the performance of five pre-soaked internal curing agents — Sodium Polyacrylate, Lightweight Expanded Clay Aggregate (LECA), Cotton fibers, Sawdust, and Perlite — combined with a water-sprinkling curing method on M25 grade concrete. Compressive strength of cube specimens was evaluated at 7, 14, and 28 days. Sodium Polyacrylate yielded the highest 28-day compressive strength of 28.83 MPa, exceeding the control mix (26.56 MPa), while LECA followed closely at 27.57 MPa. The findings demonstrate that selecting internal curing agents can reduce external water demand while maintaining or enhancing structural performance, offering a sustainable and scalable curing solution for water-stressed construction environments.