严寒环境下磷酸镁水泥材料早期性能研究

Research on Early Performance Optimization for Magnesium Phosphate Cement Materials in Severe Cold Environment

针对当前常用于道面修复的硅酸盐系水泥在严寒环境(-20℃)下水化趋于停滞,强度生成困难的问题,选择在负温环境下仍能正常水化的磷酸镁水泥作为研究对象,研究了水灰比、硼砂掺量、聚羧酸减水剂掺量、萘系减水剂掺量对严寒环境下磷酸镁水泥早期性能的影响规律,并给出了最优配合比。研究结果表明,严寒环境下水灰比的增加会降低抗折强度,延长凝结时间,但对于抗压强度影响较小;硼砂掺量与强度基本呈先增加后降低的趋势,在5%时强度表现较好;随聚羧酸减水剂的增加抗压强度呈先增加后减小的趋势,抗折强度在1 h呈同样规律,后期则呈负相关。萘系减水剂掺量则与强度呈负相关。因此,严寒环境下配合比建议选择为水灰比0.16,硼砂掺量5%,聚羧酸减水剂掺量0.4%。研究结果可为严寒环境机场道面快速修复工程提供理论支撑。

Aimed at the problems that the hydration of Portland cement commonly used in pavement repair is tending towards stagnation, and the strength is difficult to generate under severe cold environment ( -20 °C ),a magnesium phosphate cement is selected which can still hydrate normally under negative temperature environment. The effects of water-cement ratio(W/C), borax content, polycarboxylate superplasticizer content and naphthalene superplasticizer content on the early performance of magnesium phosphate cement in severe cold environment are studied, and the optimal ratio is given. The results show that the increase of W/C in cold environment enables to reduce the flexural strength and prolong the condensation time, but has little effect on the compressive strength. The borax dosage and strength basically show a trend of increasing first and then decreasing, and the strength performance is better at 5%. With the increase of polycarboxylate superplasticizer, the compressive strength shows a trend of increasing first and then decreasing. And the flexural strength shows the same law at 1 h, and then shows a negative correlation at the later stage. The content of naphthalene superplasticizer is negatively correlated with strength. Therefore, this paper recommendes to choose the mix ratio of 0.16 W/C, 5% borax dosing and 0.4% polycarboxylate superplasticizer dosing in the cold environment. The results of this paper can provide a theoretical support for the rapid repair of airport pavement in the severe cold environment.