Effect of glass powder on the mechanical and drying shrinkage of glass-fiber-reinforced cementitious composites

Abstract

Ordinary Portland concrete (OPC) is characterized by low tensile strength and low toughness. These properties can be improved by adding glass fiber (GF). However, the alkaline environment of the pore solutions adversely affects the durability of GF. First, the effect of GF addition on the mechanical properties and fluidity of cement mortar was investigated. It was found that the fluidity decreased, and the flexural strength increased with an increase in the GF content. The incorporation of GF had little effect on the compressive strength of mortar. The optimal volume dosage of GF was 2 %. Then, Experiments were conducted to study the effects of glass powder (GP) characterized by different particle sizes and dosages on the fluidity, mechanical properties, and strength activity index (SAI) of glass-fiber-reinforced cementitious composites (GFRC). The results revealed that the fluidity, flexural strength, and compressive strength of GFRC containing GP increased with a decrease in the GP particle size. The flexural and compressive strength of GFRC first increased and then decreased with an increase in the GP content. The SAIs values of all GFRC specimens were more than 75 %, except GPI-25. Finally, the effect of the GPIV (GP of the optimal particle sizes) content on the drying shrinkage and pore structure of GFRC was studied. It was observed that the addition of GP into GFRC resulted in a reduction in the drying shrinkage, and the drying shrinkage of GFRC decreased with an increase in the GPIV content. The pore volume (0.5–50 nm) of GFRC decreased with an increase in the GPIV content. GP in GFRC consumed calcium hydroxide (CH) to produce calcium silicate gel. This helped reduce the extent of corrosion of GF by CH. Waste glass is processed into GP and added into mortar or concrete to replace parts of cement to reduce cement consumption and carbon dioxide emission. This helps protect the environment. GP is a promising agent for the fabrication of glass-fiber-reinforced cementitious composites.