The mechanical and structural behavior of infrastructure and buildings under high-temperature environment is one of the major concerns in retrofit technologies. The present study aims to experimentally investigate the effectiveness of dispersed micro-fibers on the tensile behavior of uncoated carbon textile-reinforced mortar (TRM) after exposure to high temperatures. The main experimental parameters include the micro-fiber type, fiber volume fraction, and high-temperature level. Micro-steel fibers and amorphous metallic fibers with lengths of 13 and 15 mm, respectively, were utilized in this study to ameliorate the cementitious mortar matrix with a volume fraction in the range of (0.4–0.8) %. Three investigated temperature levels were 25 °C (ambient condition), 200 °C, and 400 °C. The tensile tests were carried out based on RILEM TC 232-TDT after specimens cooled down to ambient temperature. The experimental results indicate that the inclusion of micro-steel and amorphous metallic fibers within the mortar matrix significantly ameliorated the tensile characteristics of TRM specimens at both ambient and high temperatures. In addition, micro-amorphous metallic fibers exhibited significant advantages compared with steel fibers to improve the crack stress after exposure to 200 °C. Based on the experimental results and material characteristics, this study proposed an analytical model to predict the tensile strength after exposure to high temperatures and the idealized tensile stress-strain curves at the ambient temperature, of TRM composites incorporating dispersed micro-fibers, and the model prediction showed a good correlation with the experimental results.

高温环境下基础设施和建筑物的机械和结构性能是改造技术中的主要问题之一。本研究旨在通过实验研究分散的微纤维在暴露于高温后对未涂覆的碳纤维增强砂浆（TRM）的拉伸行为的有效性。主要的实验参数包括超细纤维类型，纤维体积分数和高温水平。在这项研究中，分别使用长度分别为13和15 mm的微钢纤维和非晶态金属纤维来改善水泥砂浆基质的体积分数在（0.4–0.8）％的范围内。研究的三个温度水平分别为25°C（环境条件），200°C和400°C。样品冷却至环境温度后，根据RILEM TC 232-TDT进行拉伸测试。实验结果表明，砂浆基体中包含微钢和非晶态金属纤维可显着改善TRM试样在环境和高温下的拉伸特性。另外，与钢纤维相比，微非晶态金属纤维在暴露于200°C后改善裂纹应力方面显示出显着优势。根据实验结果和材料特性，本研究提出了一种分析模型，以预测掺有分散微纤维的TRM复合材料在高温下的拉伸强度以及在室温下的理想拉伸应力-应变曲线。