Surface Microstructure of Basalt Fiber after Surface Modification and Mechanical Properties of Concrete Reinforced with Modified Basalt Fiber

Abstract

To increase the surface roughness of basalt fiber (BF) and heighten its adhesion to the concrete matrix, three types of modified solutions were prepared [nanosilica (NS) solution, γ-aminopropyl triethoxy silane (KH550) solution, and NS and KH550 hybrid solution] to modify the surface of BF. After treatment with the modified solutions, scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy were used to analyze the changes in the surface microstructure of the BF. The effects of BF modified by different solutions on the mechanical properties of basalt fiber concrete (BFC) were studied by compressive strength and splitting tensile tests. The results showed that the three types of modified solutions improved the roughness of the BF surface. However, the improvements in roughness differed, with the pure NS solution being less effective. The NS and KH550 hybrid solutions exhibited the most significant modification effects, and the roughness of the BF surface increased as the NS and KH550 contents increased. BF treated with the modified solution improved the compressive and tensile strengths of the BFC. In terms of mechanical improvements, the modification effect of the pure NS solution was the worst. The NS and KH550 hybrid solutions demonstrated the best performance. The pure KH550 solution was in between the other two solutions. In general, the mechanical properties of the BFC improved with increasing NS and KH550 contents. When microstructure and macroscopic mechanical properties were comprehensively considered, the modification effect was better when NS was 5% and KH550 was 2.91%.