【摘要】 随着我国城市化进程的加速，大量的危房、旧房进行拆除重建，产生了大量废旧混凝土等建筑垃圾。当前建筑垃圾的排放不仅造成了大量土地资源的浪费，还对环境造成了二次污染。另一方面，混凝土行业对砂石等骨料的需求日益增加，天然砂石的消耗及开采对生态环境的影响也是一个亟待解决的问题。因此，如何使建筑垃圾作为再生骨料利用成为当前关注的热点问题之一。建筑固废破碎后直接作为再生骨料使用，常存在孔隙率大、吸水率高、强度低等缺点，导致其所制备的再生混凝土强度较低、耐久性较差。因此，再生骨料在混凝土中的有效利用受到了限制。为此，研究者们对再生骨料改性开展了系统性的研究，以期实现资源的再利用。再生骨料的强化手段可分为去除黏附砂浆和强化黏附砂浆两类方法，去除黏附砂浆强化手段主要包括酸处理强化、机械研磨处理强化、热处理强化、热研磨处理强化、物理自净强化等方法，相比于强化黏附砂浆方法，去除黏附砂浆存在能耗大、强化不全面等缺陷。强化黏附砂浆主要包括微生物矿化强化、碳化处理强化、矿物掺合料改性强化和聚合物浸渍强化等方法，微生物矿化强化再生骨料效果最为显著，该方法主要是利用微生物矿化现象产生碳酸钙沉淀对孔隙进行填充，具有无污染和能耗低的特点，但该方法强化因素不易控制；矿物掺合料改性强化再生骨料是利用矿物掺合料与再生骨料表面氢氧化钙发生二次反应对骨料表面孔隙进行填充，加上纳米级颗粒的填充作用完成强化，性能提升明显，但在工程应用上常因条件控制不佳而影响强化稳定性；总之，各种强化方法各有利弊，单一的强化手段效果往往不佳。因此，应对两种或两种以上的强化方法进行复合，扬长补短，以达到较理想的强化效果。本文综述了再生骨料的发展趋势、骨料回收工艺、再生骨料性能缺陷以及再生骨料强化方法，总结分析了相关研究中存在的问题，并展望了其发展前景，以期为建筑垃圾的处理及作为再生骨料的利用提供一定的理论支持。更多还原

【Abstract】 With the acceleration of urbanization in China, a large number of dilapidated and old houses have been demolished and rebuilt, generating considerable amount of construction and demolition(C&D) waste such aswaste concrete. At present, the production of C&D waste not only occupies large quantities of land resources, but also causes secondary pollution to the environment. On the other hand, the consumption and exploitation of natural aggregate on ecological environment is also an urgent problem to be solved due to the increasing demand for aggregates such as sand and gravel in concrete industry. Therefore, how to recycle the C&D waste as aggregate has become one of the hot issues． Construction waste could directly be used as recycled concrete aggregate(RCA) after crushing. However, due to its disadvantages of large porosity, high water absorption and low strength, the use of RCA as aggregate tends to make the recycled aggregate concrete(RAC) product inferior in strength and durability, which limits the effective utilization of RCA. Therefore, many researches have been carried out on the modification of RCA in order to facilitate its reuse． The technical routes to the enhancement of RCA can be classified into removing attached mortar and strengthening attached mortar. The methods of removing attached mortar mainly includes acid treatment, mechanical grinding treatment, thermal treatment, heat grinding treatment,autogenous cleaning treatment, etc. Compared with the route of strengthening attached mortar, the removal of attached mortar has defects such as large energy consumption and incomplete strengthening. The strengthening of attached mortar can be realized by means of microbial mineralization treatment, carbonation treatment, mineral admixtures treatment, polymer emulsion treatment, etc. The process of microbial mineralization can fill the pores by produce calcium carbonate precipitate. It displays the best strengthening effect for RCA and features no pollution and low energy consumption, but the control of the strengthening factors is difficult nevertheless. The action of mineral admixtures treatment relies on the secondary reaction between mineral admixture and calcium hydroxide on the surface of RCA, as well as the filling effect of nanometer particles, resulting in obvious performance improvement of RCA. However, its strengthening stability is often reduced owing to the poor condition control in engineering applications. In a word, each strengthening method has certain advantages and disadvantages, and thus the single use of any individual method has nearly undoubted limitation in efficacy, which the combination of two or more enhancement methods can help to overcome． This review mainly summarizes the development trend, recovery technology, performance defects and enhancement methods of RCA, and also proposes some problems deserving attention and our preliminary understanding about the future directions. The paper is expected to provide certain theoretical support for relevant engineering and technological research.更多还原