To improve the durability of geopolymer recycled aggregate concrete based on waste concrete powder (WCP), and realize its application and promotion, this study utilized WCP, fly ash (FA), and ground granulated blast-furnace slag (GGBS) as raw materials, and recycled concrete aggregate (RCA) as aggregate, with Nano-SiO₂ as the modifying material to prepare WCP-based geopolymer recycled concrete (WCPGRC). The carbonation depth, uniaxial compressive strength (UCS), and dynamic elastic modulus (DEM) of WCPGRC without Nano-SiO₂ (P-WCPGRC) and with Nano-SiO₂ (NS-WCPGRC) were investigated. The phase composition, microstructure morphology, and pore distribution characteristics of the two WCPGRCs were investigated using XRD, SEM, and MIP tests. The mechanism of influence of Nano-SiO₂ on the carbonation effect and microstructure of WCPGRC was revealed. The findings demonstrate that: (1) The carbonation depth of P-WCPGRC was higher than that of NS-WCPGRC, and both increased linearly with the carbonation times. (2) Both UCS and DEM of P-WCPGRC were lower than those of NS-WCPGRC, and both showed a two-phase change, with the inflection point from a rapid to a slow increase in UCS and DEM occurred on day 7 for P-WCPGRC, while the inflection points for NS-WCPGRC occurred on the day 14. (3) The addition of Nano-SiO₂ generated more geopolymer gels, changed the microstructure, reduced the porosity, changed the pore size distribution, and enhanced the physical and mechanical properties and carbonation resistance of WCPGRC. It is feasible to improve the durability of WCPGRC by adding Nano-SiO₂.

为提高废旧混凝土粉（WCP）基聚合物再生骨料混凝土的耐久性，实现其应用和推广，本研究以WCP、粉煤灰（FA）和磨细粒化高炉矿渣（GGBS）为原料，以再生混凝土骨料(RCA)为骨料，以纳米SiO ₂为改性材料，制备WCP基地聚物再生混凝土(WCPGRC)。研究了不含纳米SiO ₂的WCPGRC (P-WCPGRC) 和含纳米SiO _{2 (NS-WCPGRC) 的}碳化深度、单轴抗压强度(UCS) 和动态弹性模量(DEM)。通过 XRD、SEM 和 MIP 测试研究了两种 WCPGRC 的相组成、微观结构形貌和孔分布特征。_{揭示了纳米SiO 2}对WCPGRC碳化效果和微观结构的影响机制。研究结果表明：（1）P-WCPGRC 的碳化深度高于 NS-WCPGRC，且均随碳化次数线性增加。(2) P-WCPGRC的UCS和DEM均低于NS-WCPGRC，且均呈现两相变化，P-WCPGRC的UCS和DEM由快速增加到缓慢增加的拐点出现在P的第7天。 -WCPGRC，而NS-WCPGRC的拐点出现在第14天。 (3)纳米SiO _2的添加产生了更多的地质聚合物凝胶，改变了微观结构，降低了孔隙率，改变了孔径分布，增强了物理性能。以及WCPGRC的机械性能和抗碳化性能。_{通过添加Nano-SiO 2}来提高WCPGRC的耐久性是可行的。