Thermomechanical behavior of textile-reinforced geopolymer concrete based on mineral-impregnated carbon-fibers (MCFs) composites

Abstract

State-of-the-art textile reinforcements are well employed to strengthen, rehabilitate or build new structures, whilst polymeric impregnation degrades considerably in elevated temperatures or aggressive environments. Herein, mineral-based matrices are regarded as a viable and novel technique. This study introduces a methodology to manufacture 2D-textile reinforcements using mineral-impregnated carbon fiber (MCF) automatically via a pultrusion and robotic–based structuring process. The reinforcing ability of MCF textiles without and with surface modification in geopolymer (GP) concrete was compared to commercial epoxy-impregnated textiles. After thermally stimulated rapid solidification, the resulting grid-like structures were incorporated into the concrete matrix. The MCF-GP-concrete composites were evaluated regarding their load-bearing capacity from 20 °C to 200 °C. Digital Image Correlation (DIC) and μCT analysis were used to study damage processes and interphase adhesion. The results demonstrated that GP concrete components with MCF textiles exhibited superior thermal resistance and a bi-linear stress-strain behavior compared to polymer matrix composite. Dilatometry and TGA measurements provided shrinkage and dehydration evidence for the thermally induced strength decrease. The enhanced chemical compatibility achieved via GP impregnation facilitates the formation of finely distributed crack patterns with reduced crack widths, contributing to improved durability scenarios and failure behavior of textile-reinforced concrete (TRC).