Compressive Bearing Capacity and Ductility of Slurry-Infiltrated Fiber Concrete Blocks with Two-Dimensional Distributed Steel Fibers

Abstract

Slurry-infiltrated fiber concrete (SIFCON) has excellent potential for application as a new material with good crack resistance, impact resistance, and seismic performance. In this paper, SIFCON blocks were cast in a single pour using the custom-made two-dimensional directional steel fiber placement device, followed by compressive testing. Based on the test results, the effects of fly ash substitution rate, steel fiber aspect ratio, and steel fiber volume fraction on the compressive bearing capacity and ductility of SIFCON blocks were investigated. The results indicate that the custom-made device in this paper effectively achieves the directional placement of steel fibers, offering a cost-effective solution that optimizes the construction process. Regarding the test results, it was observed that the compressive bearing capacity of SIFCON blocks decreases linearly with increasing fly ash substitution rate, while the addition of fly ash improves the ductility of the blocks. Notably, a 31% decrease in bearing capacity was noted when the fly ash substitution rate increases from 0% to 40%, whereas the ductility ratio increased by 99% for the same substitution rate range. Furthermore, the results revealed a positive correlation between the bearing capacity and ductility of SIFCON blocks with higher steel fiber aspect ratios and volume fractions. Specifically, the bearing capacity increased by 19% and 33% with steel fiber aspect ratio increments from 33 to 70 and volume fraction increases from 10% to 14%, respectively. Additionally, the ductility ratio of the test blocks increased by 104% when the aspect ratio of the steel fibers increased from 33 to 70, and by 37% when the volume fraction of steel fibers rose from 10% to 14%.