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 ℃),a magnesium phosphate cement is selected which can still hydrate normally under negative tem-perature environment.The effects of water-cement ratio(W/C),borax content,polycarboxylate super-plasticizer content and naphthalene superplasticizer content on the early performance of magnesium phos-phate 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 condensa-tion 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 in-crease 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 correla-tion 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.
关键词
严寒环境/磷酸镁水泥/聚羧酸减水剂/萘系减水剂/力学性能/工作性能
Key words
severe cold environment/magnesium phosphate cement/polycarboxylate superplasticizer/naph-thalene superplasticizer/mechanical properties/working performances
维普
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