The use of recycled concrete aggregates (RCA) as a replacement in new concrete has gained popularity worldwide as a method of reducing natural aggregate consumption. Many engineers, owners, and agencies are reticent to use RCA due to a lack of understanding on how the material will impact overall concrete properties. This lack of acceptance has been hindered by the difficulty of doing large-scale studies because of the time and cost of casting different concrete mixtures. Many individual studies have been completed but little work has been done to analyze that work to make broad conclusions on RCA concrete mechanical properties. This paper presents the development and analysis of a database of mechanical properties of concrete containing coarse RCA generated from 115 peer-reviewed journal articles. A sensitivity study of RCA systems was conducted through a full-factorial analysis to explore how the mixture design proportions influence the RCA concrete hardened properties. On average, the compressive strengths of concrete systems with 20% or less RCA replacement were 2% lower than that of the natural aggregate systems. Increased levels of RCA replacements decreased the average concrete compressive strengths with the highest average strength loss, in which a 10% reduction compared to natural aggregate systems is observed at 100% RCA replacement level. Results indicate that, in general, adequate concrete strengths for a variety of applications can be achieved at all replacement ratios of coarse RCA. Impacts of mixture design properties on particular mechanical properties are presented along with bivariate contour plots that can be used by concrete mixture designers to better estimate RCA concrete properties. This work supports an increased adoption of RCA by providing broad conclusions supported by statistical analysis that show typical performance of RCA concrete across a variety of design inputs.

作为减少天然骨料消耗的一种方法，使用再生混凝土骨料（RCA）替代新混凝土已在世界范围内普及。由于缺乏对材料如何影响混凝土整体性能的了解，许多工程师，业主和代理商不愿使用RCA。由于浇铸不同混凝土混合物的时间和成本，难以进行大规模研究阻碍了这种缺乏接受的态度。已经完成了许多单独的研究，但很少进行分析工作来对RCA混凝土的力学性能做出广泛的结论。本文介绍了从115篇经同行评审的期刊文章中生成的包含粗RCA的混凝土力学性能数据库的开发和分析。通过全要素分析对RCA系统进行了敏感性研究，以探索混合物设计比例如何影响RCA混凝土的硬化性能。平均而言，RCA替代率为20％或更少的混凝土系统的抗压强度比天然骨料系统的抗压强度低2％。RCA替代水平的提高使平均混凝土抗压强度降低，平均强度损失最高，其中在100％RCA替代水平下，与天然骨料体系相比降低了10％。结果表明，总的来说，在粗粒RCA的所有替代比例下，都能获得足够的混凝土强度以用于各种应用。提出了混合料设计性能对特定机械性能的影响以及混凝土混合料设计人员可以用来更好地估算RCA混凝土性能的双变量轮廓图。这项工作提供了广泛的结论，并得到了统计分析的支持，这些结论显示了RCA混凝土在各种设计输入中的典型性能，从而支持了RCA的广泛采用。