Dynamic Mechanical Properties of Slag Mortar with Alkali-Resistant Glass Fiber

Abstract

To investigate the influence of alkali-resistant glass fiber on the dynamic mechanical properties and microstructure of slag cement mortar (SCM), five SCM blocks with different volumes of alkali-resistant glass fiber (0%, 0.25%, 0.5%, 0.75%, and 1%) were prepared. A split Hopkinson pressure bar (SHPB) test device with a diameter of Φ50 mm was used to test the impact compression under different loading pressures. In this way, the stress–strain curve of SCM under average strain rates corresponding to different loading air pressures is obtained, and the relationship between the ultimate toughness, the dynamic increase factor (DIF), and the fiber content of SCM can be comprehensively analyzed in combination with the dynamic and static mechanical parameters. Research results showed that, with the increase in fiber content, the static compressive strength of the SCM showed a trend of first increasing and then decreasing, where 0.75% can be the optimal one with the maximum compressive strength. Under the impact load, the dynamic compressive strength of the SCM had a positive correlation with the average strain rate. Within the strain rate range of 75.03 s−1~141.47 s−1, When the fiber volume content is 0.75%, the dynamic compressive strength, ultimate toughness and DIF of SCM are higher than those of other groups, showing good impact resistance. According to the analysis of SEM images, the bonding performance between alkali-resistant glass fiber and cement matrix was strong, and the fibers were interlaced in the mortar to form a network structure, which has a good effect on toughening and strengthening the SCM.