Fatigue behavior of GFRP-reinforced ECC link slabs under variable stress levels and number of cycles

Abstract

Glass Fibre Reinforced Polymer (GFRP) bars have been used in the Province of Ontario as top layer of bridge deck reinforcement near surfaces exposed to de-icing chemicals. The intent of replacing deck reinforcements with GFRP is to mitigate negative effects of conventional steel rebar corrosion. Furthermore, the development of Engineered Cementitious Composite (ECC) with inherent crack width control and strain-hardening tensile behaviour for link slab application provides design engineers with a new effective way to construct joint-free bridge decks with improved durability. This paper presents experimental investigation of ECC-link slabs reinforced with sand-coated GFRP bars. The link slab specimens were subjected to variable mean fatigue stress levels of up to 55% load capacity and fatigue cycles of up to 1 million, followed by post-fatigue monotonic loading to failure. Link slab load–deflection, stiffness degradation, end rotation, GFRP and ECC strains, crack development, failure modes, energy absorbing capacity, and ductility were determined. Results were then compared with companion steel-reinforced ECC link slabs in the literature to quantify benefits of using GFRP bars. Experimental results showed that GFRP-reinforced link slabs failure by concrete crushing due to high rupture strength of GFRP, whereas steel-reinforced link slabs failed by rebar yielding. Besides exhibiting improved overall strength, the GFRP reinforced ECC link slabs showed greater post-fatigue residual rotational capacity, lower rate of stiffness degradation, enhanced post-fatigue retention of energy absorbing capacity.