Experimental Study on the Impact Resistance of Polymer-Modified Steel Fiber-Reinforced Recycled Aggregate Concrete

Abstract

Recycled aggregate concrete (RAC), composed of aggregates sourced from construction solid waste, has garnered significant attention owing to its notable environmental friendliness. In this study, waterborne epoxy resin (WER) and steel fibers (SFs) were introduced into the RAC to enhance its performance. Orthogonal tests were meticulously designed, with the substitution rate of recycled aggregate (RA), SF dosage and WER dosage as variable factors, to comprehensively analyze the splitting tensile strength and impact resistance of concrete. The impact resistance of concrete was investigated via the drop weight test method. Furthermore, scanning electron microscopy (SEM) was employed to scrutinize the microstructure of concrete, investigating the modification mechanism of WER. The results indicated that the addition of SFs exerted the most pronounced influence on the properties of RAC. As the addition of SFs increased from 0 to 1.0%, there were significant enhancements in the splitting tensile strength and impact energy of the specimens. WER exhibited notable improvements, primarily on the splitting tensile strength, while demonstrating an adverse effect on the impact resistance. Utilizing the Weibull distribution theory, the results of the impact tests were fitted and analyzed to predict the impact life of different mixtures. The predicted results showed high correlations with the measured values.