Study on synergistic improvement of rheological properties of magnesium oxysulfate cement slurry by additives
Junfu Fu, Junru Zhang, Ying Xiong, Jiahao Chen, Bin Li, Jimeng Feng, Bo Wang, Xiping Ma
Abstract
Magnesium oxysulfate cement (MOSC) is an excellent low-carbon cement, but its low flow properties limit its application in the grouting of fractured surrounding rocks in tunnels. Therefore, in this study, the rheological properties of MOSC slurry were adjusted by incorporating admixtures. Based on the indoor rheological tests, the rheological model of MOSC slurry was established, and the synergistic modification mechanism of citric acid (CA), boric acid (BA) and calcium lignosulfonate (CLS) on the rheological properties of MOSC slurry was analysed. The results showed that the rheological evolution of the modified MOSC slurry was in accordance with the Modified Bingham model. The contents of CA, BA and CLS were positively correlated with the flow properties of the slurry, with CLS having a stronger ability to improve the rheological properties of the slurry. The blocking effect of CA, the blocking effect and electrostatic repulsion effect of BA, and the dispersing effect of CLS were the main reasons for the enhancement of the rheological properties of MOSC.