Role of fiber dosages and lengths on the mechanical strength, shrinkage, and pore structure of CO2-cured amorphous metallic-fiber-reinforced belite-rich cement composites

Abstract

The impact of varying dosages and lengths of amorphous metallic fiber (AMF) on the mechanical strength, shrinkage, and pore structure of fiber-reinforced cementitious composites cured in water and in a carbonation chamber were assessed. This study evaluated fourteen mortar mixes, i.e., seven mixes for traditional water curing and seven for CO2-curing (60% relative humidity, 20 °C, and 10% CO2 concentration). The outcomes reveal that the compressive and flexural strength are significantly augmented for the mixes reinforced with AMFs as compared to the control mix (fiber-free mix), and this behavior is more pronounced with increased dosages and lengths of the AMF. Furthermore, compared to the control mix, significant mitigation in the development and magnitude of shrinkage was recorded with increased dosages and lengths of the AMF. The porosity and voids were all increased in the samples with AMF as compared to the control mix. The carbonation-cured specimens exhibited significantly higher mechanical strength, fewer voids, and higher shrinkage than those cured in water. Based on the experimental findings, it is recommended to use 0.50% volume of AMF and a length of 20 mm to produce fiber-reinforced cement composites, as this combination provides outstanding performance among all mixes tested here.