Zhang Junxiang, Li Bo, Wang Bo, Qu Lina, Liu Qi, Zhu Daohe
School of Energy & Environment Engineering, Zhongyuan University of Technology, Zhengzhou, Henan 451191, China.
School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan 454003, China.
ACS Omega. 2022 Jul 12;7(29):25380-25393. doi: 10.1021/acsomega.2c02334. eCollection 2022 Jul 26.
A new cement-based sealing material, which used Portland cement (PC) as a raw material and supplemented several gel components, such as accelerant, alkali activator, suspension agent, expansion agent, reinforcing agent, was prepared in this work. The effects of these components on the fluidity, setting time, and expansion rate of these sealing materials were investigated by an orthogonal test. The results show that the water-cement ratio and the reinforcing agent content, the accelerant content and the water-cement ratio, and the expansion agent content and the accelerant content are the most important influencing factors on fluidity, setting time, and expansion rate, respectively. In addition, the regression models and response surfaces of the factors were established using a multiple linear regression method. By this means, the influences of the two main factors on each performance of this sealing material were accurately and intuitively reflected for obtaining the optimal value in the optimization area. The results indicate that the sealing materials possess the best performances when the water-cement ratio is 1.1, the accelerant content is 50%, the expansion agent content is 0.1%, and the reinforcing agent content is 3%, which is corresponding to a fluidity of 360-380 mm, an initial (final) setting time of 60 (80)-80 (100) min, and an expansion rate of 2-12%. Furthermore, the microstructures of the optimized sealing material also reveal that the main hydration products of PC are transformed from layered Ca(OH) crystals into fine needle-like AFt crystals and C-S-H gels by the promotion effect of the optimizing ratio, thus leading to a more compact structure of optimized cement-based sealing materials.
本研究制备了一种新型水泥基密封材料，该材料以波特兰水泥（PC）为原料，并添加了几种凝胶组分，如促凝剂、碱激发剂、悬浮剂、膨胀剂、增强剂。通过正交试验研究了这些组分对密封材料流动性、凝结时间和膨胀率的影响。结果表明，水灰比与增强剂含量、促凝剂含量与水灰比、膨胀剂含量与促凝剂含量分别是影响流动性、凝结时间和膨胀率的最重要因素。此外，采用多元线性回归方法建立了各因素的回归模型和响应面。通过这种方式，准确直观地反映了两个主要因素对该密封材料各项性能的影响，以便在优化区域内获得最优值。结果表明，当水灰比为1.1、促凝剂含量为50%、膨胀剂含量为0.1%、增强剂含量为3%时，密封材料具有最佳性能，此时流动性为360 - 380mm，初凝（终凝）时间为60（80）- 80（100）min，膨胀率为2 - 12%。此外，优化后的密封材料微观结构还表明，在优化配比的促进作用下，PC的主要水化产物由层状Ca(OH)晶体转变为细小的针状AFt晶体和C-S-H凝胶，从而使优化后的水泥基密封材料结构更加致密。
