Laboratory evaluation of chemical resistance of pultruded GFRP dowels for concrete pavement

摘要

This paper presents mechanical, microstructural and physical characterization of glass fibre-reinforced polymer (GFRP) rods used as dowels for concrete pavement exposed to different types of conditionings. Two types of GFRP dowels fabricated with polyester and vinylester resins were studied. GFRP dowels were exposed to different alkaline and saline solutions at 23 A degrees C during 90 days to simulate the effect of the concrete environment. GFRP dowels were also subjected to cyclic freezing and thawing. The measured short beam shear strengths and flexural modulus of elasticity of the GFRP dowels before and after exposure were considered as a measure of the durability performance of the specimens. In addition, Fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy were used to characterize the aging effect on the GFRP dowels. The results showed the very high long-term durability of vinylester GFRP dowels exposed to tap water, CaCl2, NaOH and CaOH2 solutions, and to freeze/thaw cycles. On the other hand, the test results have shown that polyester-based GFRP dowels present an uncertain stability in the different environments simulating the field service conditions, due to plasticizing and/or irreversible chemical degradation of the polymer matrix.