Effect of fiber dosage on water permeability using a newly designed apparatus and crack monitoring of steel fiber-reinforced concrete under direct tensile loading

Cracks in concrete structures have always been the main reason to allow the aggressive and harmful agents to infringe the concrete resulting in its deterioration and decreasing lifespan. In the present study, the water permeability of the cracked concrete has been investigated. The consequences of cracking on the durability and endurance of concrete were also studied. A state-of-the-art permeability setup was designed to measure the water flow in normal and fiber-reinforced concrete under direct tensile loading. The setup was convenient for determining the average stress applied to the concrete specimens and simultaneously the maximum crack opening. Furthermore, the effect of fiber content on the cracking geometry (tortuosity and roughness) was evaluated by incorporating the coordinate data of the cracked surface using a 3D sensor-based laser scanning data acquisition system. To understand the effect of fiber content on the cracking geometry (tortuosity and roughness), the acquired data were then analyzed. Test results show that the designed setup is suitable to measure the water permeability under direct tensile loading. Water permeability decreased upon increasing the steel fiber dosage. Besides, the results show that tortuosity decreased while surface roughness increased with the fiber dosage increment. Promising preliminary results indicated that there is an inverse relationship between surface roughness and water permeability. The crack sensing setup successfully monitored the crack.