Recycled Concrete Aggregates for New Concrete Buildings for sustainability

混凝土是最通用的建筑材料之一，在上个世纪促进了工业的发展。然而，在拆除混凝土建筑时，混凝土废弃物难以处理。破碎的旧混凝土被回收作为公路路面的集料，但由于新混凝土性能的不确定性，它不用于建筑和桥梁。如果碾碎的旧混凝土可以在新建筑中回收利用，将有助于消除废物和保护天然河床岩石。该项目将继续研究将旧的碎混凝土分类，以便将其用作建筑和桥梁新混凝土的骨料。用再生混凝土制成的混凝土的强度、耐久性、长期变形等性能将被确定。随着国家基础设施的升级，可利用的废弃混凝土的数量将会增加。在新混凝土中使用这些废混凝土将减少储存废物对环境的影响，并保护河床的自然环境。用再生混凝土骨料制成的结构混凝土在建筑物和桥梁的变形、徐变和耐久性方面具有显著的可变性。该项目将进行实验和分析研究，以寻求以下问题的答案：(1)结构中回收混凝土的经济和环境效益是什么？(2)包括预应力混凝土构件在内的结构构件的长期使用荷载和设计荷载性能是什么？(3)再生混凝土骨料如何影响耐久性？(4)如果需要对破碎混凝土进行哪些修改，以提高新混凝土的性能？该项目将评估以碎混凝土为骨料制成的混凝土的力学性能。此外，由再生混凝土制成的梁和柱将在实验室进行测试，以确定结构部件的性能。最终，该项目将制定基于性能的要求、配合比设计指南、验收测试和结构设计/分析/施工指南，以实现使用再生混凝土骨料的混凝土构件的可接受性能。

Concrete is one of the most versatile building materials and has facilitated industrial growth in the last century. However, it is difficult to get rid of concrete waste when concrete buildings are demolished. Crushed old concrete is recycled as aggregates in highway pavements but it is not used in buildings and bridges because of uncertainties of performance of new concrete. If crushed old concrete can be recycled in new building construction it would help in getting rid of waste and preserve natural riverbed rocks. This project will pursue research in classifying old crushed concrete for its use as aggregate in new concrete for buildings and bridges. Properties such as strength, durability, long-term deformation will be determined for concrete made with recycled concrete. As the nations infrastructure goes through upgrading, the volume of available waste concrete will increase. Use of this waste concrete in new concrete will reduce environmental impact of storing the waste and preserving natural environment of riverbeds.Structural concrete made with recycled concrete aggregates can have significant variability in the behavior of buildings and bridges regarding deformations, creep and durability. The project will pursue experimental and analytical research to seek answers to these questions: (1) what are the economic and environmental benefits of recycling concrete in structures? (2) what are the long-term service load and design load performances of structural members, including prestressed concrete members? (3) how do recycled concrete aggregates affect durability? and (4) what modifications, if any, need to be made to crushed concrete to enhance performance of new concrete? The project will assess mechanical properties of concrete made with crushed concrete as aggregates. Also, beams and columns made of recycled concrete will be tested in laboratory to establish performance of structural components. Ultimately, the project will develop performance-based requirements, mix design guidelines, acceptance tests, and structural design/analysis/construction guidelines to achieve acceptable performance of concrete members using recycled concrete aggregates.