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随着城市化进程的加快，天然砂石资源短缺，建筑垃圾资源化成为绿色建材发展重要方向，旨在研究再生砂以（0、35%、70%、100%）的替代率对喷射混凝土力学性能的影响，结合微观形貌分析与显微硬度测试，揭示再生砂吸水对混凝土性能影响的微观机理。结果表明，随着再生砂替代率的增加，新拌喷射混凝土的坍落度、扩展度降低，最低分别达到185 mm、425 mm，喷射混凝土1 d抗压强度提高，最高可达17.8 MPa;28 d抗压强度以及劈裂抗拉强度均呈先升后降的趋势，70%替代率时最高；再生砂的掺入提升了混凝土与基底的黏结强度，28 d最高1.46 MPa。微观分析表明，再生砂表面老旧砂浆的高吸水特性在早期发挥了吸水致密化作用，有效降低了界面过渡区的局部水胶比，提升界面过渡区的密实度，后期由于再生砂自身微裂缝多、削弱了其作为空间骨架的承载能力，力学性能有所降低。
Abstract：With the acceleration of urbanization and the resulting shortage of natural sand and gravel resources, the recycling of construction waste has become a key direction for the development of green building materials. This paper aims to investigate the effect of recycled sand substitution rates(0,35%, 70%, and 100%) on the mechanical properties of shotcrete. Combined microstructural analysis with microhardness testing. The study reveals the microscopic mechanisms by which the water absorption of recycled sand affects concrete performance. The results show that as the replacement rate of recycled sand increases,The slump and slump flow of freshly mixed shotcrete decreased, reaching minimum values of 185 mm and 425 mm respectively,while the 1-day compressive strength of the shotcrete increases, reaching a maximum of 17. 8 MPa; both the 28-day compressive strength and split tensile strength exhibited a trend of initially increasing and then decreasing, peaking at a 70% replacement rate; the incorporation of recycled sand enhanced the bond strength between the concrete and the substrate, reaching a maximum of 1. 46 MPa at 28 days. Microstructural analysis indicates that the high water absorption of the old mortar on the surface of the recycled sand played a role in water-induced densification during the early stages, effectively reducing the local water-to-binder ratio in the interfacial transition zone and improving the density of the interface transition zone. In the later stages, however, the numerous microcracks in the recycled sand itself weakened its load-bearing capacity as a spatial skeleton, resulting in a decline in mechanical properties.
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基本信息:
DOI：10.19740/j.2096-9872.2026.04.14
中图分类号:TU528.53
引用信息:
[1]赵瀚第,邓松文,周文娟,等.再生砂对喷射混凝土力学性能的影响及微观分析研究[J].北京建筑大学学报,2026,42(04):135-142.DOI:10.19740/j.2096-9872.2026.04.14.
基金信息:
科技部国家重点研发计划项目（2022YFC3803403）
2026-08-25
2026-08-25