Print Email Facebook Twitter Recycling of End of Life Concrete Fines into Hardened Cement and Clean Sand Title Recycling of End of Life Concrete Fines into Hardened Cement and Clean Sand Author Lotfi, Somayeh (TU Delft Materials and Environment) Rem, P.C. (TU Delft Materials and Environment) Date 2016-05-24 Abstract 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˚C 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˚C. 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. Subject C2CA-Concrete RecyclingRecycled Concrete FinesRecycled CementRecycled Hardened Cement To reference this document use: http://resolver.tudelft.nl/uuid:6fc21e23-91d6-4b90-8a95-f367bdc089e2 DOI https://doi.org/10.4236/jep.2016.76083 ISSN 2152-2197 Source Journal of Environmental Protection, 7, 934-950 Part of collection Institutional Repository Document type journal article Rights © 2016 Somayeh Lotfi, P.C. Rem Files PDF JEP_2016052414372069.pdf 7.07 MB Close viewer /islandora/object/uuid:6fc21e23-91d6-4b90-8a95-f367bdc089e2/datastream/OBJ/view