Sulfate attack resistance and reliability analysis of recycled aggregate concrete

The aim of the present study is to investigate the effects of recycled coarse and fine aggregates on the resistance to sulfate (SO42-) attack of recycled concrete under dry-wet cycles. Six groups of different ratios of tests with coarse and fine aggregates were designed to determine the dynamic elastic modulus and mass loss of recycled aggregate concrete. A reliability analysis was carried out by using the Wiener probabilistic method; finally, the product was analyzed by scanning electron microscopy-X-ray diffraction microscopic test. The results show that in the process of sulfate attack, with the increase in the number of dry-wet cycles of sulfate, the relative dynamic elastic modulus and mass loss of recycled aggregate concrete show a trend of increasing first and then decreasing. The performance of the recycled coarse aggregate concrete specimens against sulfate dry-wet cycles is lower than that of the recycled fine aggregate concrete specimens. The use of recycled coarse aggregates results in a significant reduction in the resistance of concrete to sulfates until the concrete specimens are destroyed. The Wiener probability method can be used to effectively describe the degradation process of the sulfate resistance of recycled aggregate concrete specimens. This allows reliability assessment of the sulfate-resistant damage of recycled aggregate concrete and quantitative analysis so that its sulfate-resistant performance becomes more digital and predictable.