Carbon Sequestration, Mechanical Properties and Carbonation Kinetics of PP-Fiber-Reinforced Cement-Based Composites with CO2-Curing Treatment

The development of sustainability and high toughness in cement-based composites with polypropylene (PP) fiber is becoming increasingly important for future buildings, while CO2-curing treatment at early ages is precisely a promising technique for it. The present work reported the carbon sequestration and the mechanical property variations of different cement-based composites with and without PP fiber, 10% silica fume, and varied w/b ratios of 0.25 and 0.18. Carbonation–hydration kinetics of CO2-cured cement-based composites was also focused on. It was found that PP fiber promoted the CO2 uptake of cement-based composites with the utilization of two separate evaluation methods; the maximum CO2 uptake reached almost 11.0% in B-2 samples. The samples with enhanced carbon sequestration showed an obvious colorless area from the outside surface extending to the center. A much more drastic carbonation heat flow and heat release behavior than the subsequent hydration heat was also revealed in cement-based composites with CO2-curing treatment. Hence, this study provides an alternative way of using CO2-curing treatment on PP-fiber-reinforced cement-based composites to develop sustainable cement-based composites in the future.