文章基本信息

标题：Recycling of End of Life Concrete Fines into Hardened Cement and Clean Sand
本地全文：下载
作者：Somayeh Lotfi ; Peter Rem
期刊名称：Journal of Environmental Protection
印刷版ISSN：2152-2197
电子版ISSN：2152-2219
出版年度：2016
卷号：07
期号：06
页码：934-950
DOI：10.4236/jep.2016.76083
语种：English
出版社：Scientific Research Publishing
摘要：One of the massive by-products of concrete to concrete recycling is the crushed concrete fines, that is often 0 - 4mm. Although the construction sector is to some extent familiar with the utilization of the recycled coarse fraction (>4 mm), at present there is no high-quality application for fines due to its moisturized and contaminated nature. Here we present an effective recycling process on lab scale to separate the cementitious powder from the sandy part in the crushed concrete fines and deliver attractive products with the minimum amount of contaminants. For this study, a lab scale Heating-Air classification system was designed and constructed. A combination of heat and air classification, resulted in a proper separation of finer fraction (0 - 0.250 mm), from coarser fractions. Heating of the materials was followed by ball milling to enhance the liberation of the cementitious fraction. Experiments were carried out at different heating temperatures and milling durations. Experimental results show that by heating the materials to 500℃ for 30 seconds, the required time of ball milling is diminished by a factor of three and the quality of the recycling products satisfies well the market demand. In addition, the removal of contaminants is complete at 500℃. The amount of CaO in the recovered finer fraction from the recycling process is comparable with the amount of CaO in low-quality limestone. By using this fraction in the cement kiln as the replacement of limestone, the release of the chemically bound CO2 could be reduced by a factor of three.
关键词：C2CA-Concrete Recycling;Recycled Concrete Fines;Recycled Cement;Recycled Hardened Cement