Abstract

Along with the growing development of countries around the world, there are huge amounts of construction and demolition works which produce large volumes of recycled concrete aggregate (RCA) and these are increasing over the past few decades. One of the more practical ways to manage the RCA wastes is through re-using them as aggregate to produce concrete. In this paper, 5–10 mm crushed RCA was used at different ratios (0, 25%, 50%, 75%, and 100% by weight) in modified self-compacting concrete (SCC) to study its feasibility as natural aggregate (NA) substitute. The results show that while the presence of RCA reduced the mechanical strengths and increased the water absorption as well as permeable voids of SCC, these effects were less pronounced compared to the use of RCA in normal vibrated concrete. Although the micro-hardness of the RCA-mortar interface was lower, the thickness of the ITZ was similar as that for NA-mortar interface. These findings suggested that SCC is a suitable matrix for incorporating RCA and based on the investigated properties, it is recommended that the maximum replacement level of RCA to be 25%.

Graphic Abstract

中文翻译：

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研究再生混凝土骨料对自密实混凝土硬化性能的影响

摘要

随着世界各国的不断发展，有大量的建筑和拆除工程产生大量的再生混凝土骨料（RCA），并且在过去的几十年中，这些建筑在不断增加。处理RCA废物的一种更实用的方法是通过将其作为骨料再利用来生产混凝土。在本文中，在改性自密实混凝土（SCC）中以5-10 mm的碾碎RCA以不同的比例（0、25％，50％，75％和100％的重量比）使用，以研究其作为天然骨料的可行性（ NA）替代品。结果表明，尽管RCA的存在降低了SCC的机械强度并增加了SCC的吸水率和渗透性空隙，但与在普通振动混凝土中使用RCA相比，这些影响并不那么明显。尽管RCA-砂浆界面的显微硬度较低，但ITZ的厚度与NA-砂浆界面的厚度相似。这些发现表明，SCC是掺入RCA的合适基质，并且根据研究的性能，建议将RCA的最大取代量提高到25％。

图形摘要