Performance evaluation of recycled aggregate concrete incorporating limestone calcined clay cement (LC3)
Performance evaluation of recycled aggregate concrete incorporating limestone calcined clay cement (LC3)
复制标题
掺有石灰石烧粘土水泥的再生骨料混凝土的性能评价（LC3）
DOI：
10.1016/j.jclepro.2022.132820
复制
发表时间：
2022-07-04
影响因子：
11.1
通讯作者：
Hu, Biao
中科院分区：
文献类型：
--
作者：
Guo, Menghuan;Gong, Guoqiang;Hu, Biao
掺入石灰石煅烧粘土水泥(LC3)的再生骨料混凝土(RAC)有望解决建筑材料自然资源的枯竭问题，是缓解高耗能水泥生产对环境影响的一种方式。三元粘结剂体系对RAC基质的相组成有很大影响，水化反应动力学从形成初期开始发生变化。孔结构明显细化，孔隙率降低。改善的微观结构有助于显著提高RAC的抗氯离子渗透性能，而不显著影响其机械强度。与参照组相比，掺50%LC3的RAC在300d时氯离子快速迁移系数的降低率可达94%，而强度损失率仅为12%。使用LC3的RAC的电阻也得到显著改善，这是因为形成了更致密的基质以及减少了LC3共混物孔道溶液中的有效OH-。根据生命周期评估分析，由于水泥是碳排放和能源消耗的最大贡献者，RAC的环境影响显著降低，最大降幅为42%。再生骨料和LC3的结合是改善再生混凝土的整体性能和减轻混凝土生产的环境影响的一种很有前途的方法。
Recycled aggregate concrete (RAC) incorporating limestone calcined clay cement (LC3) holds promise as a so-lution to the depletion of natural resources for construction materials and is a way to mitigate the environmental impacts of energy-intensive cement production. The ternary binder system demonstrates an overwhelming in-fluence on the phase assemblage of RAC matrix, and the kinetics of hydration reaction are altered from the early formation stage. The pore structure is significantly refined, and the porosity is reduced. The ameliorated microstructure contributes to the significant improvement of the chloride penetration resistance of RAC without noticeably compromising its mechanical strength. For RAC incorporating 50% LC3, the reduction ratio of the chloride rapid migration coefficient could reach 94% while the strength loss ratio is only 12% at 300 days compared to the reference group. The electrical resistance of RAC using LC3 is also remarkably improved because of the formation of a denser matrix as well as the reduction of available OH- in the pore solution of LC3 blends. According to a life cycle assessment analysis, the environmental impact of RAC is significantly reduced with the maximum reduction ratio being 42% due to the incorporation of LC3 because cement is the largest contributor to both carbon emissions and energy consumption. The combination of recycled aggregate and LC3 is a promising approach to improving the overall performance of RAC and mitigating the environmental impacts for concrete production.