Implementation of two-stage mixing approach to improve the performance of fiber reinforced concrete for sustainable construction

Abstract

Concrete has a significant impact on the environment, and the use of fibers in concrete is a way to mitigate its environmental impact. In this study, two-stage mixing approach (TSMA), typically utilized to enhance the quality of the interfacial transition zone (ITZ) of recycled aggregate concrete mixtures, was employed to enhance the performance fiber reinforced concrete (FRC) mixtures by improving the fiber–matrix ITZ. To investigate the effectiveness, FRC mixtures were prepared using standard (ordinary) and modified (TSMA) mixing approaches. Subsequently, their mechanical properties were measured, and microstructural analyses were conducted to examine fiber–matrix ITZ. In the end, a case study for a concrete pavement was carried out to examine the effect of improved performance on the cost and environmental impact of FRC. Based on the results, up to a 30.6% increase in FRC residual flexural strength ratio was obtained for modified mixing method, without considerable change in strength and stiffness. Microstructural analyses were found to support the ITZ improvement provided by the employed mixing methodology. Furthermore, material-related cost and environmental impact values were found to decrease up to 6% based on the case study conducted. As a result, the implementation of TSMA for FRC was found to be a promising technique to enhance FRC performance and suggestions were provided for the future studies to further improve the obtained benefits.