Investigation of the Workability, Strength, and Durability of Fiber-Reinforced High-Performance Concrete with Full Aeolian Sand

Abstract

The application of aeolian sand as the full aggregate to produce high-performance concrete is significant for engineering construction in desert areas. However, high-performance concrete with full aeolian sand (FA-HPC) is characterized by a low water-binder ratio, high content of cementitious materials, and no restriction of coarse aggregates, resulting in a high risk of shrinkage cracking. The main purpose of this work is to investigate the reinforcement effect of different types of fibers and their combinations on FA-HPC. Three types of fibers, i.e., steel fiber (SF), basalt fiber (BF), and polyvinyl alcohol fiber were employed in the FA-HPC matrix to explore the most promising reinforcement method. The workability, strength, shrinkage, cracking resistance, and chloride resistance of FA-HPC were investigated by laboratory tests. Moreover, the fiber-reinforcement mechanism was analyzed in terms of the micromorphology of FA-HPC. The results indicated that the incorporation of fibers could improve the previously mentioned properties except for the decrease of fluidity with content dependence, especially for 12 mm fibers. The single SF has a considerable advantage in strength enhancement and shrinkage reduction presenting a variation of 56.7% and 19.5% at 1% by volume, respectively. Moreover, the hybrid fibers exhibited better behavior in durability showing 95.88% crack reduction and 48.5% improvement in chloride resistance. Eventually, two selected schemes were recommended presenting for 1% by volume single SF and hybrid fibers (0.75% by volume SF with 0.25% by volume BF) from an integrated perspective. Furthermore, microscopic characterization revealed that the mechanism of fiber reinforcement mainly played a bonding and bridging effect, refining the pores at different scales and making the structure of FA-HPC dense. This research can optimize the material composition of FA-HPC and promote the utilization of aeolian sand resources.