Evaluating the Impact of Incorporating Polypropylene Fibers with Slag Aggregate on Mitigating Cracking in Concrete Bridge Decks Using Direct Tension Test

ABSTRACT The long-term durability of concrete bridge decks is significantly influenced by their capacity to resist cracks, which can develop because of autogenous shrinkage, drying shrinkage, thermal effects, and external loading. Slag aggregate concrete has been used to minimize crack propagation in reinforced concrete decks. However, limited research has been performed to evaluate the tensile strength of slag aggregate concrete made with 100 % coarse slag aggregates. This study presents a systematic evaluation of the direct tensile behavior of concrete with 100 % coarse slag aggregate incorporating PP fibers of varying lengths and contents. In the current study, electric arc furnace (EAF) slag was used as a source of slag aggregate. Thirteen slag concrete mixtures were prepared, incorporating polypropylene (PP) fibers with varying lengths (19, 38, and 57 mm) and concentrations (0 %, 0.25 %, 0.5 %, 0.75 %, and 1 % by volume). A new test method was adopted to apply a uniaxial force on the concrete specimens. The results showed that incorporating 100 % EAF slag aggregate can produce structural concrete with adequate compressive strength. It was also noted that the PP fibers significantly affect the tensile strength. The inconsistent tensile strength results were attributed to the effect of PP fiber length in slag aggregate concrete, which impeded the mixing process and caused clumping during slurry pouring. It was recommended that further investigation is required to determine the optimal fiber length and content that affects the performance of the slag concrete. The tensile strength of concrete was also compared with the code provisions. It was observed that code provisions do not accurately predict the tensile strength of slag concrete mixtures with and without fiber.