Study on the Mechanical Behavior of Fiber-Reinforced Recycled Sands Derived from Construction and Demolition Waste

In this study, the strength and permeability properties of recycled concrete aggregate and waste brick powder obtained from construction and demolition wastes were investigated under the effect of different mixing ratios and alkali solution molarities. Sisal fiber, a natural fiber type, was applied to the soil samples prepared with recycled concrete aggregates and alkali solution-brick powder mixtures at different lengths, and the effect of the fiber additive was evaluated. For this purpose, alkali solution mixture-recycled soil was mixed at 15%, 20%, and 30% ratios. In order to determine the effect of an alkaline environment, alkali solution molarities were applied as 0.5M, 1M, 1.5M, 2M, and 2.5M. Fiber additive was applied at a constant rate, in lengths of 10 mm, 15 mm, and 20 mm. The results were evaluated with unconfined compressive strength and permeability tests. In addition, the behavior of soil samples under load was also investigated by considering the values of maximum unconfined compressive strength and axial strain corresponding to maximum strength test results. The results of this study showed that the mixture ratios were effective on the unconfined compressive strength and that the strength values increased as the mixture ratio increased. It was determined that the increase in the molarity of the alkali solution was more effective in increasing the strength compared to the mixture ratios and that this effect increased even more as the mixture ratio increased. It was observed that the fiber additive provided an increase in both the maximum strength and the strain values corresponding to these values and that it had positive effects on the load-carrying capacity and behavior of the soil. According to the permeability test results, it was evaluated that this soil improvement technique used could also be used for permeable soil surface layers.