The Impact of Carbonation Curing on the Fatigue Behavior of Polyvinyl Alcohol Engineered Cementitious Composites (PVA-ECC)

Use of Engineered Cementitious Composites (ECC) has been proven to enhance structural fatigue resistance and reduce the use-phase emissions for transportation infrastructure. Carbonation curing offers an opportunity to reduce the embodied carbon of ECC via direct CO2 sequestration. In this study, the impact of carbonation curing on ECC's fatigue resistance was examined. ECC's CO2 uptake, static flexural behavior, flexural fatigue performance, and single fiber pull-out behav-ior were studied experimentally. Midspan deflection up to 3 million cycles under fatigue load, fatigue stress-life relation-ship, and failure mechanism for carbonation-cured and air-cured ECC were investigated. Carbonation curing was found to significantly improved the fatigue life of ECC and lowered the midspan deflection under the same stress. Further, CO2- cured ECC can achieve >20% CO2 uptake per cement mass after 24-hour carbonation curing. Carbonation curing in-creased ECC's flexural strength by 32% and promoted crack width control capability, with maximum post-fatigue crack width reduced from 148 mu m to 76 mu m. The positive impact of carbonation curing on the fatigue behavior of ECC simul-taneously lowers the embodied and operational carbon of ECC structural members subjected to fatigue loading during service.