Evaluating post-fire residual impact resistance of alkali-activated slag systems

This is the authors' abstract. We don't add key points for this paper.

Cement-based mortar is a widely used construction material employed in both civilian and military structures. In military applications, mortar, which is often used as an outer layer on walls, can be subjected to impact loads caused by missiles and bombs. During such attacks, elevated temperatures resulting from fires can further intensify material degradation. Extensive research has examined the performance of cement-based materials under these conditions. However, limited studies have investigated the behaviour of alkali-activated mortars. Therefore, this study evaluated the behaviour of alkali-activated slag (AAS) mortar under impact loads after exposure to elevated temperatures. AAS mixtures with various activator dosages and moduli were exposed to 200°C, 400°C, and 600°C before testing. Results indicated that lower activator dosages and moduli were associated with higher residual compressive strength after exposure to elevated temperatures. In addition, increasing the activator’s silica modulus was found to improve performance under impact loads after exposure to elevated temperatures. However, a higher Na2O% increased the formation of hydration products, thereby making the mortar more susceptible to thermal degradation due to their decomposition.