Surface modification of magnesium oxide and its effect on the performance of magnesium phosphate cement

Liu, Mengliang; Lai, Zhenyu; Deng, Qiubai; Xiao, Rui; Liu, Zhi; Luo, Xuanzhang; Lu, Zhongyuan; Lv, Shanshan

doi:10.1016/j.conbuildmat.2021.125880

Cited by 15 publications

(1 citation statement)

References 45 publications

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“…Borax is commonly used as retarder at room temperature; in low dosing (B/M < 10%), MPC setting time is often only 8 min or less, while, in high dosing (B/M > 10%), there will be a great loss of MPC strength [25]. The surface modification of MgO using sodium water glass after heat treatment can effectively prolong the setting time of MPC without adversely affecting its later performance [26,27]. There are no studies on the negative temperature of modified MgO.…”

Section: Introductionmentioning

confidence: 99%

Effect of Modified Magnesium Oxide on the Properties of Magnesium Phosphate Cement under a Negative Temperature Environment

Luo

Lai

et al. 2022

Materials

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As a rapid repair material, magnesium phosphate cement (MPC) can be used under various environmental temperature conditions, but different temperatures significantly impact its strength and working performance. In this study, based on the surface modification of magnesium oxide, the working and mechanical properties of samples were investigated at an ambient temperature of −5 °C, and the hydration properties and microstructure of MPC were investigated using X-ray diffraction (XRD), thermogravimetric analysis (TG), mercury-in-pressure (MIP), and scanning electron microscopy (SEM). The results show that the modified magnesium oxide at a negative temperature prolongs the setting time of MPC from 10 min to more than 30 min, and fluidity can still be maintained or increased after half an hour. From 1 d to 28 d, the compressive strength growth rate of the reference group was 257.0% compared to 723.8% for the 10 wt% water-glass-modified MgO sample. K-struvite transformed from a blocky growth to a needle-like growth with the modified sample filling the pores and cracks inside the matrix. Compared with the unmodified sample, MPC’s porosity decreased from 9.62% to 9.23% for 10 wt% water-glass-modified MgO. Therefore, the surface modification of magnesium oxide not only prolonged the setting time but also further benefited mechanical performance, which provides the prerequisites for MPC construction in negative-temperature environments.

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Section: Introductionmentioning

confidence: 99%