Effect of residual slurry of recycled fine aggregate on rheological properties and strength of concrete

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Feb.2024, Vol.47 No.2: 220-225

DOI: 10.3969/j.issn.1003-5060.2024.02.012

Authors

HU Li $ ^{1,2} $, ZHAN Binggen $ ^{1,2} $, HONG Li $ ^{1,2} $, ZHANG Zhaoqiang $ ^{1,2} $, LI Jingzhe $ ^{1,2} $, CHEN Yuyang $ ^{1,2} $

(1. School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China; 2. Engineering Research Center of Low-carbon Technology and Equipment for Cement-based Materials of Ministry of Education, Hefei 230009, China)

Abstract and Keywords

Abstract: Quantitative characterization experiments on the residual slurry of recycled fine aggregate were carried out, as well as conventional concrete workability tests, rheological properties tests and mechanical properties tests to investigate the effects of different residual slurry mass fractions on the rheological and mechanical properties of recycled fine aggregate concrete. It is found that the removal of residual slurry on the surface of recycled aggregate can significantly improve its basic properties, and the use of recycled fine aggregate will accelerate the slump and expansion loss, increase the yield stress and decrease the plastic viscosity of fresh concrete. As the mass fraction of residual slurry of recycled fine aggregate decreases, the compressive strength and splitting tensile of the recycled concrete prepared with it subsequently increase. When the mass fraction of slurry is 14.9%, the aggregate-cement interfacial transition zone is tightly bonded, and the 28 d compressive strength and splitting tensile strength of recycled fine aggregate concrete are 28.50 and 2.30 MPa, respectively, which are about 89% and 77% of those of normal concrete. Therefore, the recycled fine aggregate with lower residual slurry mass fraction can replace natural sand in concrete applications.

Keywords: recycled concrete; recycled fine aggregate; residual slurry mass fraction; rheological properties; mechanical properties

作者信息

胡立 $ ^{1,2} $，詹炳根 $ ^{1,2} $，洪丽 $ ^{1,2} $，张赵强 $ ^{1,2} $，李景哲 $ ^{1,2} $，陈语阳 $ ^{1,2} $

(1. 合肥工业大学土木与水利工程学院，安徽合肥 230009；2. 水泥基材料低碳技术与装备教育部工程研究中心，安徽合肥 230009)

摘要和关键词

摘要: 文章开展再生细骨料残余浆体的定量表征实验、混凝土常规工作性能试验、流变性能试验和力学性能试验, 研究不同残余浆体质量分数对再生细骨料混凝土流变性能和力学性能的影响。研究发现, 再生骨料表面残余浆体的去除可以明显改善其基本性能, 再生细骨料的使用会使新拌混凝土的坍落度和扩展度损失加快, 屈服应力增大, 塑性黏度降低。随着再生细骨料残余浆体质量分数的减少, 用其制备出的再生混凝土的抗压强度和劈裂抗拉随之增大。当浆体质量分数为 14.9% 时, 骨料水泥界面过渡区粘结紧密, 再生细骨料混凝土的 28 d 抗压强度和劈裂抗拉强度分别为 28.50、2.30 MPa, 约为普通混凝土的 89%、77%, 表明较低残余浆体质量分数的再生细骨料可取代天然砂应用于混凝土中。

关键词: 再生混凝土；再生细骨料；残余浆体质量分数；流变性；力学性能

Funding

国家重点研发计划资助项目（2020YFC1909902）

合肥工业大学学报(自然科学版)

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