This article reports the effects of different dosages of silane coupling agent (KH-550) on the properties of geopolymer that have been cured for 360 days. The mineral phase formation and microstructure changes of geopolymer were analyzed combined with mechanical properties, XRD, FT-IR, SEM and ²⁹Si NMR. The results show that adding an appropriate amount of silane coupling agent can improve the toughness of geopolymer, and the best performance is obtained when the silane coupling agent content is 0.1 wt%. The highest compressive strength and flexural strength of geopolymer samples containing 0.1 wt% silane coupling agent cured for 90 days reached 51.4 MPa and 12.93 MPa, respectively. The gel phase in the geopolymer is significantly enriched after adding silane coupling agent. Combined with ²⁹Si NMR analysis, it can be seen that the doping of silane coupling agent promotes the polymerization reaction, and gradually develops towards low-aluminum bonded silica and Q⁴(0Al) structure. The decrease in Q⁴(0Al) structure of the geopolymer samples cured for 360 days indicates the weakening of the geopolymerization reaction and also explains the decrease in strength after long-term curing.

本文报告了不同剂量的硅烷偶联剂（KH-550）对固化360天的地聚合物的性能的影响。结合力学性能，XRD，FT-IR，SEM和²⁹ Si NMR分析了地聚合物的矿物相形成和微观结构变化。结果表明，加入适量的硅烷偶联剂可以提高地质聚合物的韧性，当硅烷偶联剂含量为0.1 wt％时，可获得最佳性能。固化了90天的含有0.1 wt％硅烷偶联剂的地质聚合物样品的最高抗压强度和弯曲强度分别达到51.4 MPa和12.93 MPa。添加硅烷偶联剂后，地质聚合物中的凝胶相显着富集。结合²⁹通过Si NMR分析，可以看出硅烷偶联剂的掺杂促进了聚合反应，并逐渐向低铝键合二氧化硅和Q ⁴（0Al）结构发展。固化360天的地质聚合物样品的Q ⁴（0Al）结构降低表明地质聚合反应减弱，也说明了长期固化后强度降低。