Experimental Research on Anti-freezing and Thawing Performance of Basalt Fiber Reinforced Fly Ash Concrete in the Corrosive Conditions

Abstract

Basalt fiber reinforced fly ash concrete (BFRFAC) is a new inorganic nonmetal composite construction material with excellent mechanical properties that could be widely used for bridge floors, pavements, and other construction engineering projects. The anti-freezing and thawing performance of BFRFAC in the corrosion circumstances was studied in detail with a comparison to normal concrete (NC) by using quick freezing method in this work. In the control group, the mass loss rate (MLR) and relative dynamic modulus of elasticity (RDME) on BFRFAC were determined in non-corrosion environment. In the control group, the mass loss rate (MLR) and relative dynamic modulus of elasticity (RDME) on BFRFAC were determined in non-corrosion environment. In the experimental group, the RDME on BFRFAC were determined in chloride corrosion, sulfate corrosion, the complex combined corrosion of chloride and sulfate solution. Further, a scanning electron microscope (SEM) was employed to scan the meso-structure of the rupture cross-section in t-he composite material at magnifications of 500, 1000, and 1500. The gripping effect between basalt fibers and su-bstrate was quantitatively analyzed in the case of pull-out failure and fracture failure, which convincingly reveal-ed the crack resistance, reinforcement, and toughening mechanisms of basalt fibers on concrete substrate. We found that RDME decreased and its descent rate slows down when BFRFAC was exposed to freeze-thaw cycles in above-mentioned four situations. The number of freeze-thaw cycles of BFRFAC was greater than 400 in the complex case of solution corrosion. The BFRFAC cyclic lifespan could be effectively extended in contrast to NC. Moreover, make full use of volcanic ash and micro-aggregate effect of fly ash can improves the gripping effect between basalt fibers and concrete substrate. As a result, it has the potential to significantly improve anti-freezing and thawing damage capacity of BFRFAC.