水玻璃固化模拟月壤抗压强度增长机理分析

Analysis on the Mechanism of Compressive Strength Growth of Simulated Lunar Soil Solidified by Sodium Silicate

月球基地建设需要大量建筑材料,其中原位利用月壤能有效减少材料和运输成本。为了研究水玻璃固化模拟月壤抗压强度增长机理,分别进行了不同水玻璃掺量下的模拟月壤单轴抗压强度试验,X射线衍射和SEM(scanning electron microscope)电镜扫描试验,得到了水玻璃固化模拟月壤的单轴抗压强度变化规律,分析了能量变化特征和微观结构。研究结果表明:掺入适量水玻璃能提高模拟月壤的单轴抗压强度;采用掺量为5%的水玻璃,在85℃条件下养护28 d模拟月壤的抗压强度可达到3.23 MPa;此时模拟月壤的总能量和弹性能均达到最大值,随着水玻璃掺量不断增加,耗散能整体上呈现下降趋势。微观结构分析表明:水玻璃的碱激发作用和吸附作用所生成N—A—S—H凝胶、钙矾石(AFt)等水化产物填充在颗粒周围,松散的骨架颗粒通过凝胶胶结成致密的网状结构,从而使模拟月壤的强度得到提高。

Lunar base construction requires a lot of building materials.In-situ utilization of lunar soil can effectively reduce material and transportation costs.In order to study the growth mechanism of the compressive strength of the simulated lunar soil after sodium silicate solidification,the uniaxial compressive strength test of the simulated lunar soil under different sodium silicate content,X-ray diffraction and SEM scanning experiments were carried out,the uniaxial compressive strength of sodium silicate solidified simulated lunar soil were obtained,the energy evolution characteristics and microstructure were analyzed.The results show as follows.Adding a proper amount of sodium silicate can increase the uniaxial compressive strength of the simulated lunar soil.With 5%sodium silicate,the compressive strength of the simulated lunar soil can reach 3.23 MPa after curing at 85℃for 28 days.The total energy and elastic energy of the simulated lunar soil have reached the maximum value.As the content of sodium silicate continues to increase,the overall dissipation energy shows a downward trend.Microstructure analysis shows that N—A—S—H,AFt and other hydration products generated by the alkali excitation and adsorption of sodium silicate are filled around the particles.The strength of lunar soil is improved.