Effect of the addition of fibers to reinforce lightweight concrete containing multiple residues
Lightweight concrete; Residues; Steel fibers; Polypropylene fibers; Glass fibers; Carbon fibers.
The final destination of residues originated from industrial and mining activities has gained growing attention from governmental representatives involved in environmental issues. One of the economic alternatives is their use as concrete additions, exploring their potential to reduce the consumption of Portland cement and concrete weight, and at the same time improve concrete strength and durability, aiming at structural applications. In this scenario, the objective of the present study was to evaluate the effect of fiber addition on the properties of a lightweight concrete mix formulated using expanded clay and multiple residues (porcelain polishing, tire rubber and limestone residues). The volume contents of steel, polypropylene, glass and carbon fibers added to the lightweight concrete mix were 0.2%, 0.4% and 0.6%. The resulting fiber-reinforced mixes were characterized by specific weight, void ratio, water absorption slump, mechanical (compressive and tensile) strength and fracture resistance. A fiber-free mix was also prepared and characterized for reference purposes. The results revealed that the addition of fibers generally reduced the workability of the mixes, as well as their specific weight and compressive strength. On the other hand, the void ratio and water absorption increased along with the tensile strength and fracture resistance.