Study on the performance of basalt fiber geopolymer concrete by freeze-thaw cycle coupled with sulfate erosion

Abstract

In this research, double-blended materials such as fly ash and slag are used as binders, and basalt fibers (BF) are mixed in varying volume fractions (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) relative to the volume of concrete. Besides, sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) served as activators. The study investigates the freeze-thaw resistance, microstructure, performance mechanism, and internal freeze-thaw damage distribution of basalt fiber geopolymer concrete (BFGPC) through freeze-thaw cycle tests coupled with sulfate attack, SEM, and energy dispersive spectrometer analyses. The results indicated that BFGPC possesses excellent freeze-thaw resistance, achieving a minimum frost-resisting grade of F200. Increasing the BF content significantly enhances the frost resistance of the concrete. The hydration products of BFGPC include C–(A)–S–H gel, C–S–H gel, and a minor amount of N–A–S–H gel, which contribute to its structural density and homogeneity. The high compressive strength of BFGPC (87.7 MPa) further contributes to its outstanding freeze-thaw durability.