Integrated evaluation of smart internal curing strategies in concrete: Mechanical, durability and SEM insights

This study investigates the influence of self-curing agents like Super Absorbent Polymers (SAPS), Polyethylene Glycol Liquid (PEGL), and Polyethylene Glycol Powder (PEGP) with various dosages on the performance of M30 grade concrete under different curing regimes like complete water, complete air, and partial air and water curing regimes. Compressive, split tensile and flexural strength Studies were evaluated alongside durability parameters such as water absorption, sorptivity, and rapid chloride permeability. Scanning electron microscopy analysis revealed enhanced hydration and densified microstructure in specimens with self-curing agents compared to Control specimens without any self-curing agent. Among the mixes, SAPS 0.3%, PEGL 1.0%, and PEGP 1.0% demonstrated optimal performance, achieving an additional strength recovery over Control Specimen without any self-curing agent under air curing regime and Water curing regime. Notably, under the 7-day air + 21-day water curing regime, SAPS 0.3% increased 28-day strength from 33.9 MPa (control) to 42.0 MPa (+24%); under 7-day air + 49-day water it increased from 41.1 MPa to 48.8 MPa (+19%). The study concludes that PEG and SAPS-based internal curing significantly recover concrete performance in terms of workability, strength and durability, especially in environments with limited access to external water curing.