Study on performance deterioration and life prediction of reed straw-recycled brick aggregate concrete after freeze-thaw cycle

The current rate of carbon dioxide emissions poses a significant threat to global climate, making it increasingly important and urgent to lead the carbon-intensive construction industry to achieve carbon neutrality. Currently, the most practical method involves reusing waste materials. In this study, waste red bricks were used to replace 75 % of natural aggregates in concrete, and three different forms of reed stalks (including reed straw ash, reed straw strips, and reed straw powder) were added to prepare the recycled reed straw brick aggregate concrete (RSAC). Freeze-thaw tests were carried out for 25, 50, 75, and 100 cycles in water and sodium sulfate solution to establish a freeze-thaw deterioration model and perform life prediction. The results showed that the degree of freeze-thaw deterioration of the specimens in sulfuric acid solution was small, and the degree of deterioration of reed powder concrete (RSAC-F) and reed ash concrete (RSAC-H) was more serious than reed strip concrete (RSAC-T) and additive-free concrete (RSAC-0). After 100 water freeze-thaw cycles, the strength losses of the specimens were 21.55 %, 21.7 %, 18.71 %, and 20.54 %, and the relative dynamic elastic modulus losses were 6.11 %, 7.25 %, 4.39 %, and 5.79 %, and the mass losses were 1.79 %, 2.04 %, 1.4 %, and 1.5 %. The fitting results showed that the predicted values of the parabolic model and two-parameter Weibull distribution damage model were closer to the experimental values, and the fitting rates are both greater than 90 %. The life prediction results show that the freeze-thaw resistance of the four types of reed-brick aggregate recycled concrete can reach more than 80 years in southern China, meeting the durability requirements, and the RSAC-T and RSAC-0 group concrete could also be used in projects with lower frost resistance requirements in the north region of China.