Enhancing chloride ion permeability resistance of recycled aggregate concrete through internal curing with glazed hollow beads

This study explores the effects of glazed hollow beads (GHB) dosage and additional water amount on the capillary negative pressure, mechanical properties, initial resistivity, and electric flux in conditions where recycled aggregate concrete (RAC) is subject to cracking. The chloride ion (Cl-) diffusion coefficient for RAC cured internally was evaluated using the resistivity method, which also looked at the relationship between the diffusion coefficient, GHB dosage, and additional water amount. This analysis advances our understanding of the functional mechanisms of pre-soaked GHB in RAC. The research reveals that incorporating pre-soaked GHB enhances RAC in two primary ways. Firstly, pre-soaked GHB acts as an internal curing agent that stimulates the formation of hydration products, thereby filling internal voids and mitigating micro-crack development. Secondly, it functions as an adsorbent. The differential in relative humidity and internal pressure between the unsaturated GHB and the cement stone matrix promotes the sequestration of corrosive agents in cracked RAC. Additionally, an internal curing impact factor has been introduced, forming the basis of a new model to calculate the Cl- diffusion coefficient that accounts for both GHB dosage and additional water intake. The established quantitative relationships between resistivity, electric flux, and Cl- diffusion coefficient in GHB-treated RAC (GHB-RAC) provide a methodological framework for quickly evaluating the durability of GHB-RAC against Cl- intrusion in practical engineering contexts. •Pre-soaked GHB hinder the permeation of chloride ions in RAC through internal curing and adsorption mechanisms.•A quantitative relationship has been established between the internal curing impact factor and the durability of RAC.•A rapid assessment method has been proposed to evaluate the chloride ion permeability of GHB-RAC.