Experimental study of the mechanical behavior of continuous glass and carbon yarn-reinforced mortars

This work aims to evaluate the possibilities of cementitious materials reinforcement by continuous alkaline resistant AR glass or carbon yarns. Bond flexural tests and flexural tests on 7 × 7 × 28-cm specimens were performed at various ages of the mortar and with various layouts and, volume fractions of yarn. The flexural tests showed the capacity of yarn to improve the strength and ductility of the mortar. A definition of the effectiveness of a yarn as reinforcement is given as proportional to the ratio of the post-cracking maximal load on the product of the strength of yarn and the volume fraction of yarns. The effectiveness of a yarn seems to depend on its structure: the one of the carbon yarn, made up of micrometric filaments, is lower than the one of the glass yarn, made up of millimetric strands. Losses of strength and ductility were observed between 28 days and a year for the glass yarn-reinforced mortars. For the carbon yarn-reinforced mortars, post-cracking strength increases with time.