Development of innovative lightweight shock absorbing cement based composites

冲击载荷在高速行驶的交通、打桩和飞机降落中都很常见。它特别与瓦斯爆炸、地震和爆炸事件有关。在这种动态荷载作用下，旨在承受这些事件的建筑环境见证了大量的能量突然传递给结构。因此，保护系统和防撞垫需要的材料不仅能承受冲击，而且能困住弹丸并吸收冲击。这种材料在民用（交通障碍、射击场、跑道）和军事（例如加拿大省级重建队在阿富汗的保护性建筑）的应用中都是必不可少的。基于轻质骨料和胶凝泡沫的复合材料的固有柔软性使其成为减震系统的理想候选者，前提是正确理解它们对如此严重载荷的响应。事实上，它们是一种环境友好的替代品，具有再利用工业废料作为补充胶结外加剂（来自阿尔伯塔省北部的煅烧油砂尾矿）和轻质骨料（来自加拿大埃德蒙顿附近燃煤热电厂的底灰）的巨大潜力。不幸的是，我们并不完全了解轻质水泥基材料在冲击载荷下的反应。没有预测模型存在，这阻碍了设计和利用这类显然有前途的建筑材料。因此，迫切需要表征密度对高加载速率下水泥基材料断裂力学的影响。该方案将优化和模拟在冲击下的纤维增强轻质胶凝复合材料。在此基础上，将开发各种民用和军用减震水泥基复合材料。此外，它还将探索埃德蒙顿附近工业废物的再利用可能性。

Impact loading is a common occurrence in fast moving traffic, pile driving and aircraft landing. It is specifically associated with gas explosion, earthquakes, and blast events. During such dynamic loads, the built environment intended to withstand these events witnesses a large amount of energy suddenly imparted to the structure. Therefore, protective systems and crash cushions require materials which not merely survive the impact but in fact trap the projectile and absorb the shock. Such materials are essential in applications, both civil (traffic barriers, firing ranges, runways) and military, such as in protective construction by the Canadian Provincial Reconstruction Team in Afghanistan. The inherent softness of composites based on lightweight aggregates and cementitious foams makes them an ideal candidate for shock absorbing systems, provided their response to such severe loading is properly understood. In fact, they make for an environment-friendly alternative with excellent potential for the re-use of industrial waste products as supplementary cementing admixtures (calcined oil-sands tailings from Northern Alberta) and lightweight aggregates (bottom ash from coal fed thermal plants in the vicinity of Edmonton, AB). Unfortunately, we do not fully understand how lightweight cement-based materials respond under impact loading. No predictive models exist and this hinders design and utilization of this decidedly promising class of construction materials. Therefore, there is a tremendous need to characterize the effect of density on the fracture mechanics of cement-based materials at high loading rates. This proposal will optimize and model fiber-reinforced lightweight cementitious composites under impact. Based on this, it will develop shock absorbing cement-based composites for a variety of civil and military applications. In addition, it will explore the possible re-use of industrial waste in the vicinity of Edmonton, AB.