石膏种类对富水充填材料凝结硬化性能与机理的影响

针对富水充填材料的凝结性能受石膏种类影响的问题,采用X射线衍射、扫描电镜、红外光谱等微观实验,分析富水充填材料硬化体的组成,探讨二水石膏和半水石膏对富水充填材料性能影响的机理. 结果表明:以硫铝酸盐水泥-石膏-石灰为主的富水充填材料体系中,为保证正常的凝结硬化,石膏应为二水石膏;如以半水石膏为原材料,在7d龄期时仍不具有强度;二水石膏充足时生成的钙矾石晶体呈细针状,二水石膏不足时生成的钙矾石晶体为六棱短柱状;富水充填材料的强度主要来源于硫铝酸盐水泥-石膏-石灰反应生成的钙矾石,而不是水泥自身水化的水化硫铝酸钙、铝胶和氢氧化钙.

Impact of gypsum type on the setting and hardening performance and mechanism of water-rich filling materials

As for the problem that different gypsum types have different influence on the condensation performance of water-rich filling materials, micro experiments, such as X-ray diffraction, scanning electron microscopy and infrared spectroscopy, were used to analyze the composition of the hardened body and investigate the influence of dihydrate gypsum and hemihydrate gypsum on the setting and hardening characteristics of water-rich filling materials. It is found that in a water-rich filling material system of sulphoaluminate cement-gypsum-lime, the gypsum type should be dihydrate gypsum so as to ensure the normal condensation setting and hardening;if hemihydrate gypsum is used as a raw material, the water-rich filling material has not strength after hydrating for 7 d. When dihydrate gypsum is adequate, the generated ettringite crystals are fine needle-like; but when dihydrate gypsum is inadequate, the generated ettringite crystals are short hexagonal columnar. The strength of the water-rich filling material is mainly derived from ettringite genera-ted by the reaction of sulphoaluminate cement gypsum and lime, rather than the hydration products of cement generated by itself such as hydration calcium sulphoaluminate, alumina gel and calcium hydroxide.