Effect of copper slag and cement by-pass dust addition on mechanical properties of concrete

This research was undertaken to study the effect of copper slag (CS) and cement by-pass dust (CBPD) addition on concrete properties. In addition to the control mixture, two different trial mixtures were prepared using different proportions of CS and CBPD. CBPD was primarily used as an activator. One mixture consisted of 5% copper slag substitution for portland cement. The other mixture consisted of 13.5% CS, 1.5% CBPD and 85% portland cement. Three water-to-binder (w/b) ratios were studied: 0.5, 0.6 and 0.7. Concrete cubes, cylinders and prisms were prepared and tested for strength after 7 and 28 days of curing. The modulus of elasticity of these mixtures was also evaluated. Results showed that 5% copper slag substitution for portland cement gave a similar strength performance as the control mixture, especially at low w/b ratios (0.5 and 0.6). Higher copper slag (13.5%) replacement yielded lower strength values. Results also demonstrated that the use of CS and CBPD as partial replacements of portland cement has no significant effect on the modulus of elasticity of concrete, especially at small quantities substitution.