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最大的建筑和拆迁（C&D）废物生产国之一，占城市固体废物的近25%。此外，由于加拿大大量基础设施已达到使用寿命，经常需要拆除以进行新的建设，因此建筑垃圾产生的趋势每年都在增加。由于它们的处理成本高昂，并且在堆填区占用大量空间，因此找到一种方法将它们重新利用，使这些大量的废物变成建筑行业的自然资源至关重要。由于基础设施需求的增加和可用替代品的减少，天然骨料资源正在迅速枯竭，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，迄今为止的挑战仍然是，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得到解决。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（如梁、柱、梁柱节点）在反循环荷载下的抗震性能，并为这些构件制定适当的设计指南。本研究还将确定由RCA制成的混凝土道路护栏的抗冲击性，并确定其有纤维和无纤维的吸能能力。预测结构构件（由RCA制成）在不同载荷条件下（地震和冲击载荷）的行为，并制定适当的设计指南，将有助于在建筑行业创造一个可持续的解决方案，让从业者、业主和承包商对使用再生混凝土产品感到舒适。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减少温室气体排放的目标。

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.