Damage prediction of recycled aggregate concrete under a sulfate attack using the seasonal ARIMA model

To promote the broader use of Recycled Aggregate Concrete (RAC), especially in saline regions and coastal areas with high sulfate levels, enhancing the resistance to sulfate damage is essential for RAC. This study examined the compressive strengths of RAC with varying fly ash contents and the water-binder ratios after exposure to sulfate wet-dry cycles. The findings indicated that the damage value of RAC defined by the loss of compressive strength under sulfate attack decreased as the fly ash content increased. In contrast, higher water-binder ratios and a greater number of sulfate wet-dry cycles led to increased damage of RAC. Considering the fly ash content and water-binder ratio, the trend moving average method was introduced to expand the data sample based on the experimental data, and a sulfate durability damage model of RAC based on the seasonal autoregressive integrated moving average (ARIMA)was proposed. Based on early compressive strength and the seasonal ARIMA model, a high fly ash content, especially not less than 20 %, and a low water-binder ratio, preferably not exceeding 0.45, is conducive to significantly enhancing the sulfate resistance of RAC. Moreover, the influence of the water-binder ratio on the sulfate resistance is more substantial than that of the fly ash content. The seasonal ARIMA model can accurately reveal the damage evolution law and predict damage of RAC with different fly ash contents and water-binder ratios under different sulfate wet-dry cycles. It provides a new method to study the durability of RAC.