Yang Yibo, Chen Baixi, Su Yan, Chen Qianpu, Li Zhiji, Guo Wenying, Wang Hengchang
School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China.
State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510640, China.
Materials (Basel). 2020 Aug 11;13(16):3535. doi: 10.3390/ma13163535.
The undesirable properties of conventional recycled fine aggregate (RFA) often limit its application in the construction industry. To overcome this challenge, a method for preparing completely recycled fine aggregate (CRFA), which crushes all concrete waste only into fine aggregate, was proposed. The obtained CRFA had high apparent density, and its water absorption was lower than that of the conventional RFA. To take advantage of the CRFA, this paper introduced the modified packing density method for the CRFA concrete mix design. The modified packing density method took account of the powder with a particle size of smaller than 75 μm in the CRFA and balanced both the void ratio and the specific surface area of the aggregate system. Concrete (grade C55) was prepared using the CRFA to validate the feasibility of the proposed method. The unit price of the prepared CRFA concrete was around 12.7% lower than that of the natural aggregate concrete. Additionally, the proposed procedure for the concrete mixture design could recycle all concrete waste into the new concrete and replace all the natural fine aggregate in the concrete mixture.
传统再生细骨料（RFA）的不良特性常常限制了其在建筑行业的应用。为了克服这一挑战，提出了一种制备完全再生细骨料（CRFA）的方法，该方法将所有混凝土废料仅破碎成细骨料。所获得的CRFA具有较高的表观密度，其吸水率低于传统RFA。为了利用CRFA，本文介绍了用于CRFA混凝土配合比设计的修正堆积密度法。修正堆积密度法考虑了CRFA中粒径小于75μm的粉末，并兼顾了骨料体系的空隙率和比表面积。使用CRFA制备了混凝土（C55级）以验证所提方法的可行性。制备的CRFA混凝土的单价约比天然骨料混凝土低12.7%。此外，所提出的混凝土配合比设计程序可以将所有混凝土废料回收到新混凝土中，并替代混凝土混合物中的所有天然细骨料。
