Unveiling the combined influence of higher molecular weight polyethylene glycol and superplasticizer chemistry on fresh, mechanical, and microstructural performance of internally cured mortar

Abstract

The limitations of conventional water curing in tall structures and arid regions necessitate alternative hydration strategies. Use of internal curing agents in high strength concrete can effectively mitigate evaporation and promote enhanced cement hydration in the concrete. However, because the superplasticizer is a required component in high strength concrete, compatibility of the internal curing agent with superplasticizer needs to be investigated. This study investigates the efficacy of internal curing (IC) using polyethylene glycols (PEGs)–PEG 4000 and PEG 6000, in conjunction with superplasticizer from two different families, polycarboxylate ether (PCE) and sulphonated naphthalene formaldehyde (SNF) in mortar mixes. A total of ten mixes were prepared for which samples from each mix were exposed to standard water curing, room curing, and internal curing. The research outcomes reveal a novel application of PEG 6000 and PEG 4000 in conjunction with PCE-based superplasticizers at optimized dosages, presenting a promising avenue for direct implementation in mortar mixes to meet both mechanical and durability prerequisites. Optimized IC mortar mixes displayed comparable or superior mechanical and durability performance to conventionally cured counterparts. This study demonstrates the potential of PEG 6000-PCE combinations as IC agents for improved fresh and hardened properties, offering a viable alternative for challenging construction environments. Further research is warranted to explore the long-term performance and economic feasibility of IC mortars in large-scale projects.