A comparative study of the thermophysical and mechanical properties of the glass fiber reinforced polymer bars with different cure ratios

Abstract

Cure ratio is a key property for the acceptance and use of glass fiber reinforced polymer bars in civil engineering infrastructure. Yet, there have been no reported studies investigating the effect of cure ratio on the physical, thermal, and mechanical properties of the fiber reinforced polymer bars. This paper presents an interlaboratory test program involving four laboratories to evaluate the cure ratio and glass transition temperature of glass fiber reinforced polymer bars from different production lots. The effect of cure ratio on the physical, mechanical, and microstructure of the glass fiber reinforced polymer bars was also evaluated. The results of this study show that the cure ratio significantly affected the glass transition temperature ( Tg) of the glass fiber reinforced polymer bars tested. The results also show that interlaminar shear strength of the glass fiber reinforced polymer bars was affected by the cure ratio but not the physical and tensile properties, microstructure, or chemical composition. The fully cured glass fiber reinforced polymer bars had interlaminar shear strength up to 8% higher than the partially cured bars. Nonetheless, the glass fiber reinforced polymer bars with a cure ratio of only 96% still had properties well above the minimum prescribed physical and mechanical properties for the reinforcing materials in concrete structures.