Optimization of eco-friendly glass fiber reinforced concretes produced using marble and slate powder by Taguchi method

In this study, the goal was to produce an environmentally friendly and cost-effective concrete by partially replacing cement with waste marble powder and slate powder. These materials were incorporated into the concrete mix at replacement levels of 5%, 10%, 15%, and 20% by mass. Additionally, to enhance the tensile strength of the concrete, glass fiber was added at varying volume fractions of 0.25%, 0.50%, 0.75%, and 1.00%. To evaluate the fresh properties of the concrete, slump and air content tests were performed. The prepared specimens were cured for 7 and 28 days to assess their hardened characteristics. After curing, the hardened concrete samples underwent compressive strength testing, splitting tensile strength testing, ultrasonic pulse velocity (UPV) analysis, and rebound hammer tests. Furthermore, some specimens were immersed in a magnesium sulfate solution for 28 days to assess their resistance to sulfate attack. These samples were then tested for compressive strength and rebound hammer values and compared to the control specimens not exposed to the sulfate solution. To identify the optimal material combinations among the various test parameters, the Taguchi method a widely recognized and statistically reliable approach was employed, using Minitab statistical software. Microstructural analysis techniques such as Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) were also utilized to examine the morphology of the produced concrete samples. Based on the results, it was observed that incorporating marble powder up to 5%, slate powder up to 10%, and glass fiber up to 0.5% had a generally positive impact on the mechanical and durability performance of the concrete.