Experimental study of the influence of the incorporation of combined recycled steel and polypropylene fibers on the compressive behavior of self-compacting cementitious composites

Abstract

In recent times, many industries have focused on affordable materials with superior mechanical properties. Most fiber-cement composites are made from a single type of fiber. The addition of the fine elements, which must include at least one mineral addition, fewer chippings, a dosage of super plasticizing admixture, and quite often a colloidal agent, can produce very workable cementitious composites that spread without any vibration in the formwork. However, the use of several types of fiber in the composite, in different proportions, offers several environmental, technological, and economic advantages that are of growing interest to manufacturers. Improving material properties, such as impact resistance, tensile strength, compressive strength, and increased rigidity, can also contribute to a significant gain in fiber. This study aims to exploit recycled steel fiber, obtained from steel wool production waste, and polypropylene fiber, as reinforcement, together with a cementitious matrix, based on local materials, to develop a new self-compacting cementitious composite with combined fibers (steel/polypropylene). Blends of 1%, 1.5%, and 2% combined fibers were formulated with steel and polypropylene fibers. Several proportions of matrix/combined reinforcement were considered to assess the effect of the amount of combined reinforcement on destructive tests, such as compressive strength, and non-destructive tests, such as sound propagation velocity and rebound index, on the quality of these composites. The results obtained show that a combination of two different fibers can be used in self-placing cement composites as reinforcement. Finally, we determine the possibility of using non-destructive testing as a means of assessing the quality of self-placing cement composites with combined fibers (steel/polypropylene).