CARBON SPHERES AS POSSIBLE MICRO-REINFORCEMENTOF CEMENT-BASED COMPOSITES

摘要

In this research, the influence of carbon spheres additive on mechanical properties of cement-carbon composites, such as flexural strength, flexural toughness and compression strength, were investigated. Carbon spheres were added to cement mortars in amount of 0.5 wt. %. Chemical treatment in hot nitric acid was applied in order to improve interfacial bonding between carbon fibres and cement mortar. It was found that the addition of carbon spheres in the amount of 0.5 wt.% to cement matrix improved its flexural toughness. The best results were obtained for cement composites subjected to chemical treatment. As proved by electrochemical measurements, during modification of carbons in nitric acid the functional groups, such as carboxyl, hydroxyl or phenol, were build up on the surface of carbon spheres. Consequently, the bonding between carbon fibres and cement matrix was enhanced.