Agricultural waste is promising to be used for lightweight building materials. The combination of geopolymer and wheat straw (WS) is adopted to produce a kind of eco-friendly lightweight composite. Using the pretreated WS by NaOH and Na₂SiO₃ solutions, the influence of WS on the properties of geopolymer-wheat straw composite (GWSC) is investigated. The pretreated WS avoids the retarding effect of the untreated WS on the hydration of geopolymer and even presents an accelerating effect. Increasing the content of pretreated WS generally results in the reduction in apparent density and strength, the GWSC with the apparent density of 1000-1500 kg/m³ can be prepared, corresponding to the 28d compressive strength between 5 MPa and 25 MPa. The water absorption linearly increases with the increases of the pretreated WS content, while an appropriate amount of the pretreated WS can enhance the water resistance of GWSC. A WS/FA ratio lower than 8% can produce the GWSC with qualified thermal insulation performance. The alkaline treatment, especially NaOH treatment, significantly improves the bonding strength between fiber and geopolymer matrix. In addition, the pretreated WS saturated by NaOH and Na₂SiO₃ solutions is beneficial to the fluidity of geopolymer-WS mixture and could act as the internal curing agents to enhance the hydration of geopolymer.

中文翻译：

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地质聚合物和麦秆制备的环保轻质复合材料

农业废弃物有望用于制造轻质建筑材料。采用地质聚合物与麦秆（WS）结合生产一种环保轻质复合材料。采用NaOH和Na ₂ SiO ₃溶液预处理的WS，研究了WS对地质聚合物-麦秆复合材料（GWSC）性能的影响。预处理的WS避免了未处理的WS对地质聚合物水化的延迟作用，甚至呈现加速作用。^{增加预处理WS的含量一般会导致表观密度和强度的降低，表观密度为1000-1500 kg/m 3}的GWSC可制备对应28d抗压强度在5MPa～25MPa之间的材料。吸水率随着预处理WS含量的增加而线性增加，而适量的预处理WS可以增强GWSC的耐水性。WS/FA比例低于8%即可生产出具有合格隔热性能的GWSC。碱处理，尤其是NaOH处理，显着提高了纤维与地质聚合物基体之间的结合强度。此外，用NaOH和Na ₂ SiO ₃溶液饱和的预处理WS有利于地质聚合物-WS混合物的流动性，并且可以作为内部固化剂增强地质聚合物的水化。