Properties of hybrid steel-basalt fiber reinforced concrete exposed to different surrounding conditions

Abstract

The use of mineral basalt fibers in composites recently attracted increasing attention because of its ecological nature, availability in abundance, excellent mechanical properties, and good resistance against chemical attacks. The long-term behavior of concrete is of great importance to concrete structural integrity, especially when subjected to acid or sulfate attack. The optimization of basalt fibers and quantitative analysis in terms of fiber factor for different environmental conditions remain a research gap. In this regard, basalt fibers of various lengths and contents, together with steel fibers, were incorporated into a tailored fly ash-CaCO3 whisker mixture to produce hybrid fiber reinforced concrete (HFRC), which was then exposed to various aggressive surrounding conditions. A new fiber factor is proposed for the HFRC, and empirical models are established for the mechanical attributes. Furthermore, scanning electron microscopy (SEM) analysis of HFRC is performed to evaluate the microstructural damage caused by chemical attacks. Significant enhancement is observed in water absorption, weight loss, and compressive strength of HFRC with the inclusion of steel fibers and basalt fibers compared to plain concrete after exposure to various hazardous environmental conditions. It is found that the mineral basalt fibers presented overall worthy suitability in developing HFRC with improved properties under aggressive surrounding conditions.