Behavior of Reactive Powder Concrete reinforced with Hybrid Fibers containing Sustainable Materials

Abstract

This study investigates the behavior of recycled Reactive Powder Concrete (RPC), made from finely ground recycled raw materials and containing a certain percentage of recycled copper (electrical waste copper wire) and steel fibers. This concrete has a relatively low water-to-binder ratio and is composed of cement, fine aggregate, and ultrafine powders, such as quartz powder and silica fume. The properties of Fiber-Reinforced Reactive Powder Concrete (FR-RPC) containing micro-steel fibers, recycled copper fibers, and a mixture of steel-recycled and copper fibers were investigated. A micro-steel fiber RPC (MF1) was used as a reference mix, having 1% steel fibers by volume with 13 mm length and 0.2 mm diameter. Recycled copper fiber RPC (MF2) was prepared utilizing 1% recycled copper fibers by volume, with a diameter of 0.2 mm and a length of 10 mm. In addition, Hybrid FR-RPC (HFR-RPC) samples were prepared by mixing micro steel fibers and recycled copper fibers in proportions of 0.5-0.5% (MF3), 0.4-0.6% (MF4), and 0.3-0.7% (MF5), respectively. The compressive strength, flexural strength, and splitting tensile strength of these FR-RPC mixes were studied. The results displayed that MF3 achieved slightly lower compressive strength, flexural strength, and splitting tensile strength than MF1 and higher than MF2, MF4, and MF5. Although the mechanical strengths of MF3 were marginally lower than those of MF1, compressive strength, flexural strength, and splitting tensile strength were almost the same. Therefore, copper wire waste fibers can be employed along with steel fibers with excellent results.