Development of innovative lightweight shock absorbing cement based composites

冲击载荷是快速交通、打桩和飞机着陆中常见的现象。它与瓦斯爆炸、地震和爆炸事件特别相关。在这种动态荷载作用下，用于承受这些事件的建筑环境突然被赋予了大量的能量。因此，防护系统和碰撞缓冲需要的材料不仅要能经受住撞击，而且实际上要能挡住弹丸并吸收冲击波。这种材料在民用(交通障碍物、射击场、跑道)和军事应用中都是必不可少的，例如在阿富汗的加拿大省级重建小组的保护性建筑中。以轻骨料和水泥基泡沫为基础的复合材料固有的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反应。事实上，它们是一种环境友好的替代品，具有良好的再利用潜力，可将工业废物用作辅助胶凝混合材(来自北艾伯塔省的焙烧油砂尾矿)和轻质集料(来自艾德蒙顿附近燃煤热电厂的底灰)。不幸的是，我们还没有完全了解轻质水泥基材料在冲击载荷下的反应。不存在预测模型，这阻碍了这种绝对有希望的建筑材料的设计和使用。因此，在高加载速率下，迫切需要表征密度对水泥基材料断裂力学的影响。这项建议将对纤维增强轻质水泥基复合材料进行优化和建模。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，它还将探索阿肯色州埃德蒙顿附近工业废物再利用的可能性。

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.