Influence of the curing conditions on the mechanical properties of alkali-activated copper slag-basalt-based thin composites

In this work, a series of composites fabricated with a matrix based on copper slag-metakaolinite and potassium silicate solution, reinforced with basalt fibers, were cured in different conditions (temperature, pressure, and time) to find the optimal curing parameters. This comparative study presents their influence on the mechanical properties of the laminates/composites produced. Differential scanning calorimetry was used to collect information on the matrix on heating till 250 °C. The use of a hot press for the curing allowed to achieve similar volume fractions and improve matrix impregnation. The flexural strength and elastic modulus were used to evaluate the mechanical performance of the samples. The results showed that 80 °C is a reasonable curing temperature. Curing the samples for 1 h at 80 °C led to flexural strength up to 100 MPa and elastic modulus up to 20 GPa. However, increasing the curing time to 2 or 3 hours was observed to have no significant effect on the optimal strength. Similarly, higher processing pressure was observed not to positively affect the mechanical properties. These results are of interest for the reuse of copper slag in the development of structural thin composites for potential building applications.