Flexural Fatigue Performance of Pavement-Grade Low-Carbon Concrete Containing Waste Clay Bricks

Abstract

This study investigated the flexural fatigue performance of pavement-grade geopolymer concrete (GPC) developed using low-carbon binders containing waste clay bricks (WCB), slag, and fly ash. Concrete was developed using two types of binders, one with a ternary blend of WCB, slag, and fly ash and one with only slag and fly ash as a full replacement for ordinary portland cement (OPC). Test specimens were subjected to flexural fatigue by four-point bending under three levels of stress which are equivalent to 75%, 80%, and 85% of the maximum static flexural strength. A two-parameter Weibull distribution was considered in the probabilistic analysis of fatigue life data, which corresponds to the number of cycles until failure. At all stress levels, GPC showed better fatigue performance compared to OPC concrete. At lower stress levels, the performance of GPC with WCB in the binder was better than the performance of conventional GPC with only slag and fly ash. However, GPC with WCB shows reduced performance at higher stress ratios. Survival probability of all concrete types (i.e., GPC and OPC concrete) decreased with increasing stress level. At a selected stress level, the fatigue life of all concrete types increased with the decrease of survival probability. The ultimate fatigue strength of GPC was higher than the OPC concrete. GPC with WCB binders showed an ultimate fatigue strength of more than 68% considering 107 repeated loading cycles. Improving sustainability within the construction industry is a current major challenge, and all the while it is becoming an indispensable necessity. Transitioning from conventional materials with high negative environmental impacts such as OPC to more sustainable alternatives can significantly enhance sustainability in the construction industry. However, absence of data regarding the overall performance of newly identified low-carbon materials is a limiting factor to the industry uptake of these alternatives. The findings from this research characterize the fatigue behavior of low-carbon concrete that is developed using WCB-based binders and designed for pavement applications specifically. Understanding the fatigue performance is crucial for any material intended for use in pavement applications. The results from the current work provide valuable insights into the targeted application of these innovative materials, addressing a critical gap in information.