Mechanical Properties and Chloride Penetration Resistance of Copper Slag Aggregate Concrete

Abstract

The authors of this paper systematically studied the mechanical properties and durability of concrete prepared with copper slag instead of natural aggregates. An analysis index was used to assess compressive strength, and a statistical method was used to establish a mix proportion design theory of copper slag aggregate concrete. The analysis was used to quantify the effect of copper slag aggregate concrete on resistance to chloride ion migration. Combined with the morphological analysis of SEM images and fractal calculations, the tests were used to explain the improvement mechanism of copper slag as a fine aggregate on concrete’s mechanics and durability from the microscopic mechanism perspective. The results showed that replacing a natural sand fine aggregate with copper slag improved the compressive strength of concrete, and the optimum replacement rate was found to be 40%. The influence of the water–cement ratio on the strength of copper slag aggregate concrete was exceptionally conspicuous—the more significant the water–cement proportion was the lower the compressive strength of the concrete. The optimum dosage of the water-reducing agent was found to be 3.8 kg/m3. A rapid chloride ion migration test and potential corrosion analysis showed that copper slag aggregate concrete’s initial density and corrosion resistance were higher than those of natural aggregate concrete. Electrochemical impedance spectroscopy analysis results showed that the structural concrete comprising copper slag aggregate instead of natural sand had a better anticorrosion effect on embedded steel bars. SEM morphology and fractal dimension analyses showed that the incorporation of steel slag aggregate decreased the initial damage to the concrete internal section.