Recycled aggregates (RA) are obtained from construction and demolished waste, laboratory crushed concrete and concrete waste at RMC plants. The concrete made from recycled aggregate is known as recycled aggregate concrete. The use of recycled aggregate is very beneficial to the environment in civil works. Its usage also helps in financial saving as the cost of transportation and production energy cost of natural coarse aggregate (NCA) is reduced. In India, the recycled aggregate application in lower grade concrete work is observed. However, the effect of recycled aggregate on the strength and durability of concrete restricts its use in higher-grade work. This paper presents a series of tests carried out on recycled coarse aggregate (RCA) and recycled coarse aggregate concrete (RCAC) and test results are compared with the NCA and parent concrete made from NCA. Tests were carried out as per IS code and concrete was prepared using a two-stage mixing approach in the concrete mix design. M30 concrete mix of four RCAC samples was tested at 28 days of curing and in comparison with parent concrete, it is found that on an average compressive strength is decreased by 12.89% at 28 days curing. Adhered mortar increases the porosity of the recycled aggregate and forms a weak zone between aggregate surface and mortar. In addition, test results showed the defects in recycled aggregate and helped to identify the area where concentration is necessary to improve the quality of recycled aggregate using six sigma DMAIC methodology. Total of 12 defects were found in the process and raw material. Statistical analysis was used to evaluate the performance of all the mix made with RCA. KeywordsRecycle aggregate, Total quality management, Recycled aggregate concrete, Six sigma, Waste recycle.

中文翻译：

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使用六西格玛DMAIC方法改进再生骨料混凝土的质量

再生骨料（RA）来自RMC工厂的建筑废料，拆除的废料，实验室压碎的混凝土和混凝土废料。由再生骨料制成的混凝土被称为再生骨料混凝土。再生骨料的使用对土建工程的环境非常有益。由于减少了天然粗骨料（NCA）的运输成本和生产能源成本，其用法还有助于节省资金。在印度，观察到再生骨料在低等级混凝土中的应用。但是，再生骨料对混凝土强度和耐久性的影响限制了其在高等级工程中的使用。本文介绍了对再生粗骨料（RCA）和再生粗骨料混凝土（RCAC）进行的一系列测试，并将测试结果与NCA和由NCA制成的母体混凝土进行了比较。按照IS规范进行测试，并在混凝土配合比设计中使用两阶段混合方法制备混凝土。在固化28天时测试了四个RCAC样品的M30混凝土混合物，与母体混凝土相比，发现在固化28天时平均抗压强度降低了12.89％。粘结的砂浆会增加回收骨料的孔隙率，并在骨料表面和砂浆之间形成薄弱区域。此外，测试结果显示了再生骨料的缺陷，并使用六西格玛DMAIC方法帮助确定了需要浓缩以提高再生骨料质量的区域。在该过程和原材料中总共发现了12个缺陷。使用统计分析来评估使用RCA制成的所有混合物的性能。关键字再生骨料，全面质量管理，再生骨料混凝土，六个西格玛，废物回收。