Investigation on the mechanical and durability performance of high-strength concrete utilizing high molarity internal curing compounds

Maintaining adequate early-age moisture is essential for achieving the desired strength and durability of concrete, particularly in harsh environments such as hot climates or deep foundation structures. This study explores the effectiveness of internal curing (IC) using polyethylene glycols (PEG 4000 and PEG 6000) of different molecular weights to improve the long-term performance of high-strength concrete. Concrete mixes incorporating PEG at 0.5–2.0% by binder weight were systematically compared with conventionally cured, spray-cured, and uncured specimens through comprehensive physical, mechanical, durability, and microstructural assessments. Results revealed that IC with PEG 6000 exhibited superior performance compared to PEG 4000, with optimal dosages of 1.0 and 1.5%, respectively, achieving or exceeding conventional curing outcomes. IC specimens demonstrated denser microstructures and reduced shrinkage. Although large-scale structural effects were beyond this study’s scope, IC concrete offers notable environmental and economic advantages by reducing water use and external curing demands, ensuring durable performance in demanding conditions.