Towards Sustainable Construction Practices: Harnessing the Potential of Pumice Powder for Eco-Friendly Concrete, Augmented by Hybrid Fiber Integration to Elevate Mechanical and Durability Performance

Abstract

The utilization/reuse of industrial wastes in construction is vital in reducing the cost of industrial operations and construction materials. The present research aims to study the effects of utilizing industrial waste, i.e., pumice powder (PP), as a partial replacement for cement. The partial pumice powder based concrete is reinforced by hybrid fibers into the concrete matrix. Seven combinations were developed for the best replacement of PP as a binder; one was a control mix, and the other six replaced the cement quantity from 10% to 35% with 5% increments. The results indicated that adding 15% PP achieves the optimum strength, which is further incorporated with hybrid fibers. Hybrid fibers comprised steel fibers (SF) extracted from waste rubberized scrap tires and polypropylene fibers (PF). Seven specimens were utilized to assess the rheological, mechanical, and durability qualities of the hybrid fiber-reinforced concrete (HyFRC): one served as a control mix (CS), three included 1% hybrid fibers (PF and SF), and three contained 2% hybrid fibers. Fresh concrete density and slump flow tests were conducted to examine the rheological properties. HyFRC mixes resulted in a low slump. The compressive, tensile, and flexural strengths were increased by up to 6.71%, 9.4%, and 18.09%, respectively. Results from energy dissipation of compressive, split tensile, and flexural strength were increased by up to 484.98%, 208.57%, and 264.83%, respectively. The assessment of HyFRC durability attributes involved subjecting the samples to a chemical attack using hydrochloric and sulfuric acid, which resulted in significant resistance to mass and strength loss for thexvii higher content of PF inclusion. Additionally, scanning electronic microscopy (SEM) confirmed the bond of concrete with hybrid fibers, and analytical characterizations of mixtures, such as energy dispersive x-ray spectroscopy (EDX), were studied. Moreover, regression models were also constructed for prediction parameters by utilizing the Popovics expression model, which is the basis for developing the prediction model for the compressive stress-strain curves in this study. The proposed analytical model resulted in close agreement with experimental results.