Development of innovative lightweight shock absorbing cement based composites

冲击荷载在快速移动的交通、打桩和飞机着陆中很常见。它特别与气体爆炸、地震和爆炸事件有关。在这种动态载荷期间，旨在承受这些事件的建筑环境见证了突然赋予结构的大量能量。因此，保护系统和防撞缓冲垫需要不仅能经受住冲击，而且实际上能捕获抛射体并吸收冲击的材料。这类材料在民用（交通障碍、射击场、跑道）和军用方面都是必不可少的，例如加拿大阿富汗省级重建队的防护性建筑。基于轻质骨料和水泥泡沫的复合材料的固有柔软性使它们成为减震系统的理想候选者，只要它们对这种严重载荷的响应被正确理解。事实上，它们是一种环境友好的替代品，具有很好的潜力，可将工业废料再利用为补充水泥混合物（来自北方阿尔伯塔的煅烧油砂尾矿）和轻质骨料（来自AB省埃德蒙顿附近的燃煤热电厂的底灰）。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肯定有前途的建筑材料。因此，有一个巨大的需要，以表征在高加载速率下的水泥基材料的断裂力学密度的影响。该建议将优化和模拟纤维增强轻质水泥基复合材料的冲击。在此基础上，它将开发用于各种民用和军用的减震水泥基复合材料。此外，该研究亦会探讨可否再利用位于安省埃德蒙顿附近的工业废物。

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.