Effect of Polypropylene Fibers on Concrete with Partial Replacement of Cement by Lime Sludge

Concrete is one of the most widely used construction materials in the world, known for its strength and durability. Cement is a crucial binding material used in construction, particularly in concrete. It is well known that cement production is not neutral for natural environment among others due to high CO2 emission. Different strategies of mitigation of negative environmental impact of its production are developed. One of the ways is utilization of supplementary cementitious materials (SCMs) in the manufacture of cement and concrete. This study investigates the effect of polypropylene (PP) fibers on the mechanical properties and Workability of concrete incorporating lime sludge as a partial replacement for cement. Lime sludge, a by-product of various industrial processes, not only minimizes cement consumption but also contributes to waste management and reduced carbon emissions. Polypropylene fibers, known for their ability to control microcracking and enhance ductility, are introduced to counteract the brittleness associated with lime-based concrete mixes. Experimental investigations were carried out by replacing cement with lime sludge (5%,10%,15%,20%) while adding polypropylene fibers in controlled dosages (0.5%,1.0%,1.5%) by overall volume. Key parameters such as workability, compressive strength, split tensile strength, flexural strength and rebound hammer test (NDT) were evaluated.