全组分废弃混凝土再生水泥熟料烧成及水化性能研究

Study of sintering process and hydration of recycled cement clinker produced from all components of waste concrete

针对我国废弃混凝土胶凝化再生利用技术存在的组分分离导致材料利用率低、生产成本和能耗高等问题,提出利用以石灰岩为粗骨料的全组分废弃混凝土作为生料原料,煅烧熟料、制备再生水泥的新思路.研究了再生水泥的生料易烧性以及熟料的矿物组成、水化强度和水化产物的微观形貌.结果表明:全组分废弃混凝土再生水泥技术是可行的;再生水泥生料易烧性较好,熟料胶砂强度低于硅酸盐水泥熟料技术要求,试验条件是影响强度的主要因素;引入熟料晶种煅烧的再生水泥熟料,其主要矿物成分和水化产物的组成与参比工业熟料基本相同,两者水化产物中C-S-H凝胶形貌相似.

With regards to the existi concrete in our country which lead to ng th technical problems for the cementitious reusage of waste e low efficiency of various component separation in waste concrete, high production cost and large energy consumption, a new technology roadmap is raised using all components of waste concrete as part raw materials and burning clinker for producing recycled cement. The burnability of recycled cement raw mixtures, the mineral components of recycled cement clinker and the strength and microstructure of hydrated recycled cement are all investigated. The experimental results show that the technology of recycled cement produced from all components of waste concrete is feasible and the burnability of raw mixtures is good. However, the strength of hydrated recycled cement mortar is lower than the technical requirements of Portland cement clinker strength, due to the difference of experimental conditions between the laboratory and plant~ sintered recycled cement clinker admixed with the seed crystals of Portland cement clinker, its mineral compositions and hydration products are basically the same as the industrial cement clinker. In addition, the microstructure of C--S--H gel in the hydration products is also similar.