Chong Linlin, Yang Jianming, Chang Jin, Aierken Ailifeila, Liu Hongxia, Liang Chaohuan, Tan Dongyong
College of Civil Engineering, Changsha University, Changsha 410022, China.
Innovation Center for Environmental Ecological and Green Building Materials of CCSU, Changsha University, Changsha 410022, China.
Materials (Basel). 2023 Jan 27;16(3):1101. doi: 10.3390/ma16031101.
This paper investigated the influence of dry-wet cycles and sulfate attack on the performance of magnesium potassium phosphate cement (MKPC) as well as the effect of waterglass on MKPC. X-ray diffraction (XRD), TG-DTG, and scanning electron microscopy (SEM-EDS) were used to examine the phase composition and microstructure of MKPC. The results showed that the flexural and compressive strength of an MKPC paste increased initially and subsequently decreased in different erosion environments. The final strength of the M0 paste exposed to the SK-II environment was the highest, while that of the M0 paste exposed to the DW-II environment was the lowest. The final volume expansion value of MKPC specimens under four corrosion conditions decreased in the following order: DW-II, M0 > SK-II, M0 > DW-II, M1 > SK-I, M0 > DW-I, M0. Compared to the full-soaking environment, the dry-wet cycles accelerated sulfate erosion and the appearance of damages in the macro and micro structure of the MKPC paste. With the increase in the number of the dry and wet cycles, more intrinsic micro-cracks were observed, and the dissolution of hydration products was accelerated. Under the same number of dry-wet cycles, the strength test and volume stability test showed that the durability in a NaSO solution of the MKPC paste prepared with 2% waterglass (M1) was superior to that of the original M0 cement. The micro analysis indicated that waterglass can improve the compactness of the microstructure of MPC and prevent the dissolution of struvite-K.
本文研究了干湿循环和硫酸盐侵蚀对磷酸镁钾水泥（MKPC）性能的影响以及水玻璃对MKPC的作用。采用X射线衍射（XRD）、热重-微商热重（TG-DTG）和扫描电子显微镜（SEM-EDS）对MKPC的物相组成和微观结构进行了检测。结果表明，在不同侵蚀环境下，MKPC净浆的抗折强度和抗压强度先升高后降低。暴露于SK-II环境的M0净浆的最终强度最高，而暴露于DW-II环境的M0净浆的最终强度最低。MKPC试件在四种腐蚀条件下的最终体积膨胀值按以下顺序降低：DW-II，M0＞SK-II，M0＞DW-II，M1＞SK-I，M0＞DW-I，M0。与全浸泡环境相比，干湿循环加速了MKPC净浆的硫酸盐侵蚀以及宏观和微观结构损伤的出现。随着干湿循环次数的增加，观察到更多的固有微裂纹，并且水化产物的溶解加速。在相同干湿循环次数下，强度试验和体积稳定性试验表明，用2%水玻璃（M1）制备的MKPC净浆在NaSO溶液中的耐久性优于原始M0水泥。微观分析表明，水玻璃可以提高MPC微观结构的致密性，并防止鸟粪石-K的溶解。
