Structural capacity and design of reinforced concrete elements made from recycled aggregate

根据加拿大统计局的数据，不列颠哥伦比亚省是建筑和拆迁(C&D)废物的最大产生地之一，C&D废物占城市固体废物的近25%。此外，建筑垃圾的产生趋势每年都在增加，因为加拿大的大量基础设施已经到了使用寿命的尽头，因为它们经常需要拆除以进行新的建设。由于它们的处置成本高昂，并且在垃圾填埋场中占据了大量的空间，因此找到一种方法对它们进行再利用，以便将这些巨大的废物转化为建筑业的自然资源是至关重要的。由于不断增加的基础设施需求和可用替代品的减少，天然骨料来源正在迅速枯竭，再生混凝土骨料(RCA)是满足需求的可行选择。为了鼓励在混凝土中使用RCA，加拿大标准协会在新的CSA标准(CSA A23.1-14/A23.2-14,2014)中纳入了一些规范。然而，到目前为止，挑战仍然是，在加拿大，使用再生骨料生产结构混凝土的适当指导方针仍然没有解决。拟议的研究将确定由不同替换水平的RCA制成的钢筋混凝土构件(例如梁、柱、梁柱节点)在反向循环荷载作用下的抗震性能，并为这些构件制定适当的设计准则。这项研究还将确定RCA混凝土护栏的抗冲击性能，并确定其在纤维和不含纤维的情况下的能量吸收能力。预测结构构件(由RCA制成)在不同加载条件(地震和冲击加载)下的行为，并制定其适当的设计指南，将有助于在建筑行业创建可持续的解决方案，使从业者、业主和承包商能够舒适地使用再生混凝土产品。采用这种可持续的做法将进一步帮助该省以及加拿大实现温室气体减排的目标。

According to Statistics Canada, British Columbia is one of the largest producers of construction and demolition (C&D) waste which contributes to almost 25% of the municipal solid waste. Furthermore, the trend of construction waste generation is increasing every year since a large volume of Canadian infrastructure has reached to the end of their service lives, as they often need to be demolished for new construction. As their disposal is costly and occupies large amount of space in landfills, it is critical to find a way to reuse them so that this huge amount of waste can be turned into a natural resource for construction industry. Since natural aggregate sources are quickly depleting due to increasing infrastructure needs and less available alternatives, recycled concrete aggregate (RCA) is a viable option to meet the demand. In order to encourage the use of RCA in concrete, Canadian Standard Association has incorporated some specifications in the new CSA standard (CSA A23.1-14/A23.2-14, 2014). The challenge, however, remains to date that the existence of proper guidelines for producing structural concrete with the use of recycled aggregate remains unresolved in Canada. The proposed research will determine the seismic performance of reinforced concrete elements (e.g., beams, columns, beam-column joints) made of RCA of different replacement level under reverse cyclic loading and develop proper design guidelines for such elements. This study will also determine the impact resistance of concrete road barriers made of RCA and determine its energy absorption capacity with and without fibers. Predicting the behavior of structural elements (made of RCA) under different loading conditions (seismic and impact loading) and developing their proper design guideline will help create a sustainable solution in construction sectors where practitioners, owners and contractors will feel comfortable of using recycled concrete products. Incorporation of such sustainable practice will further help the province as well as Canada to meet the target reduction of greenhouse gas emission.