Application of Ultrahigh-Performance Concrete and Sustainably Engineered Cementitious Composites for Link Slabs

Premature failure of expansion joints causes maintenance costs and corrosion issues. Link slabs can be an alternative to expansion joints in bridge structures, aiming to reduce these issues. The choice of material for link slabs is critical since link slabs require being sufficiently deformable to accommodate girder end rotation while ensuring narrow flexural cracks to prevent water and salt infiltration. Hence, this study compared the structural performance of link slabs made of four different materials, including ultrahigh performance concrete (UHPC), two sustainable engineered cementitious composites (ECCs), and normal concrete. Conventional ECC relies on a significant amount of portland cement (PC), a known source of greenhouse gas emissions. Therefore, this study focused on two eco-friendly ECC materials: ECC with slag (ES), which replaces 67% of PC with slag, and ECC with fly ash (EF), which substitutes 40% of PC with fly ash. Additionally, the structural performance of link slabs reinforced with different types of rebar, including 400W conventional rebars, glass fiber–reinforced polymer (GFRP) rebars, and high-strength A1035 rebars, with varying reinforcement ratios were evaluated using FEM. FEM was also used to observe the structural performance of both traditional and new types of link slabs, constructed with the mentioned concrete materials and reinforcements. The results showed that the link slab made of ES exhibited the highest deformability. The UHPC link slab was the most effective in controlling crack width, followed by the ES link slab, and then the EF link slab. Link slabs made of EF, ES, and UHPC reinforced with GFRP1 rebars exhibited 21%, 23%, and 4% increase in deformability when compared with those reinforced with 400W rebars, respectively.