文献类型：期刊文献

英文题名：Developing circular concrete: Acid treatment of waste concrete fines

作者：Ding, Tiejun[1];Wong, Hong[1];Qiao, Xiuchen[2];Cheeseman, Christopher[1]

机构：[1]Imperial Coll London, Dept Civil & Environm Engn, UKCR Adv Infrastructure Mat Lab, London SW7 2AZ, England;[2]East China Univ Sci & Technol, Sch Resource & Environm Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2022

卷号：365

外文期刊名：JOURNAL OF CLEANER PRODUCTION

收录：;EI(收录号：20222612279154);WOS:【SCI-EXPANDED(收录号:WOS:000822214200004)】；

基金：The research leading to this publication benefitted from EPSRC funding under grant No. EP/R010161/1 and from support from the UKCRIC Coordination Node, EPSRC grant number EP/R017727/1, which funds UKCRIC's ongoing coordination. We acknowledge help from the research group at East China University of Science and Tech-nology for their technical support and general discussions.

语种：英文

外文关键词：Waste concrete fines; Acid treatment; Sand; Silica-rich pozzolan; Circular concrete; Carbon sequestration

摘要：The development of circular concrete, to enable key components to be extracted and reused, is a key requirement to achieve sustainability in the built environment. Current industry practice for end-of-life concrete is best described as down-cycling because recycled concrete aggregate has limited use, with disposal of the associated crushed concrete fines. Acid treatment of waste concrete is being investigated to allow key concrete components to become circular and, in this work, the effect of acetic acid concentration, liquid/solid (L/S) ratio, reaction time and temperature on the leaching of waste concrete fines is reported. An acid concentration of 0.6 mol/L, an L/S ratio of 7 ml/g, and a reaction time of 6 h at ambient temperature allows clean sand to be extracted from concrete fines. This performs identically to new sand in mortar samples. We show for the first time that the dried and ground silica-rich residue produced by acid leaching has pozzolanic properties comparable to commercially available supplementary cementitious materials (SCM) such as blast furnace slag and coal fly ash. The potential for CO2 sequestration using the Ca(2+-)rich leached solution to form CaCO3 is calculated. The research shows that acid leaching of concrete fines can produce clean reusable sand, generates a viable SCM and sequester significant amounts of CO2 by forming precipitated calcium carbonate.