Role of copper slag on improvement of strength, quality and durability of high-strength self-compacting concrete: an industrial waste

Abstract

This paper aims at the experimental study of durability properties and long-term mechanical properties of self-compacting concrete with fly ash as secondary cementitious material and copper slag as inert material. Cement replaced with fly ash at 20% level and fine aggregate replaced with copper slag at 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%. Twelve different mixes were prepared to assess the durability properties like RCPT, Sorptivity, and UPV. The microstructure of SCC was observed using a Scanning Electron Microscope (SEM). Mechanical properties like compressive, split tensile, and flexure strength at the ages of 28, 90, 180, and 365 days were evaluated. Compressive strength with CS improved from 85.53 to 102.89 MPa, Split tensile strength varies from 4.82 to 6.74 MPa, and flexural strength changes from 11.03 to 11.82 MPa at a 40% replacement level. All mechanical properties were enhanced with the use of copper slag. Copper slag improved the resistance against chloride penetration. RCPT showed optimum at a 50% CS which was reduced from 1054.74 to 401.26 coulombs. Sorptivity with 0.013 mm/s1/2 to 0.006 mm/s1/2 for 40 and 50% also. UPV varies from 4383 to 4565 m/s. 40% copper slag partial replacement enhanced the properties of self-compacting concrete, and up to 60% of fine aggregate can be substituted with industrial copper waste. By this investigation, copper slag can be used as a sustainable building material.