Corrosion resistance of RC/UHTCC beams with various healing promoters in marine environment

Abstract

Four types of reinforced concrete/ultrahigh toughness cementitious composite (RC/UHTCC) composite beams with various healing promoters were prepared to study the effect of self-healing behavior on corrosion resistance in marine environment from the structural component level. Healing promoters included superabsorbent polymers (SAP), SAP treated with calcium solution, crystalline admixture (CA). The specimens with SAP were cured by dry-wet cycles, and other specimens were immersed curing. Self-healing behavior of crack was observed by the microscope before and after healing. Accelerated corrosion test was performed on pre-cracked specimens to test chloride permeability and corrosion resistance. The healing degree of crack was proposed based on the healing area of crack, increased by adding healing promoters, especially for CA. The corrosion resistance of four types of cracked members was improved after healing in marine environment, due to self-healing behavior of crack reducing chloride permeability. The increasing trend of corrosion resistance of four types of members was consistent with the healing degree of crack. The healing degrees of crack for specimens without healing promoters, with SAP, treated SAP and CA were 40.75%, 62.11%, 84.05% and 100%, the corresponding decrease range of corrosion ratios were 15.40%, 24.07%, 32.61% and 47.14%, respectively. This indicated that the corrosion resistance of cracked reinforced members was improved by healing promoters with excellent healing degree of crack in marine environment. The closure of crack and improvement of corrosion resistance verified that the reinforced members achieved good self-healing properties to improve the recovery of durability in marine environment from the structural component level.