FORMATION OF GLASS FIBER-CEMENT PASTE INTERFACIAL ZONE AND ITS EFFECT ON THE MECHANICAL PROPERTIES OF GLASS FIBER REINFORCED MORTAR

Microhardness measurements and EDXA analyses were made in the regions around glass fiber strands embedded in the cement paste to elucidate the effects of curing temperature and mineral admixtures on the microstructure of the interfacial zone between a glass fiber strand and cement paste matrix. The characteristics of flexural strength and toughness of glass fiber reinforced mortars were also discussed relating them to the results obtained by the microhardness measurements and EDXA analyses. Curing temperature significantly influenced the microhardness distribution patterns in the interfacial zone. Both the softest and the hardest region exist within the interfacial zone. The discontinuity in microhardness in the regions in samples cured at a high temperature (38°C) appears to greatly affect the toughness of the corresponding glass fiber reinforced mortars. Overall microhardness distribution patterns were not changed by the addition of the mineral admixtures.