The Applied Research Of Emulsified Asphalt Modified Cement Mortar On Crack Repaired In Cold Areas

Cement concrete pavement is one of the most important pavement structures in China, being widely applied in construction engineering. Under the effect of vehicle load and long-term natural environment, the concrete structure will gradually get worse and appear different degree of damage. In cold regions, under the effects of cold and endless winter, extremely low temperature, cycle of freezing and thawing and the deicing salt, the situation of damage is even more severe. Cracks are the principal damage forms. In allusion to the characteristics of cold area pavement damage and the requirement of repair materials, the study uses SBR modified emulsified asphalt to modify the cement materials based on the extensive investigation of concrete pavement crack repair material, aiming to develop the repair material for cement concrete pavement in cold area.In the study, firstly, it analyses the damage situation and mechanism of concrete pavement, and then, chooses water-cement ratio, poly-cement ratio, superplasticizer dosage and molding methods as the four key factors of the repair material properties, and gives every factor three horizontals. It chooses the initial mortar fluidity, compressive strength ratio of the third day and the twenty-eighth day as the evaluation index and uses orthogonal experimental design for visual analysis in order to explore the scope for raw materials. on the basis of the scope, determining the initial mixing ratio of SBR modified emulsified asphalt mortar.Systematic experimental study on the performance of SBR modified emulsified asphalt mortar under the conditions of different poly-cement ratios is carried out, and then the influence of SBR modified emulsified asphalt’s concent on the workability,mechanical properties, durability, shrinkage and adhesive properties is analyzed.The results showed that:①In the range of P/C≤20%, the fluidity of SBR modified emulsion asphalt mortar could be improved, and it would be the most obvious when P/C=15%. When fluidity is275mm, it could be used as the threshold of the groutability of5mm crack. The SBR modified emulsified asphalt can reduce the setting time of cement mortar. And with the increase of SBR modified emulsified asphalt, the lagging effect is more obvious.②In the range of P/C=15%-20%, SBR modified emulsified asphalt can improve the flexibility and shapeablity of the mortar effectively, and decrease the shrinkage of mortar, micro-expansion occurs at P/C=15%.③In the range of P/C=10%～20%, SBR modified emulsified asphalt can effectively improve the frost resistance, permeability and wear resistance of mortar.④The adjunction of SBR modified emulsified asphalt effectively improve the cohere effection between mortar and old matrix material, and at the range of P/C=15%～20%, the cohere effection is the best.Through X-ray diffraction and pore structure tests, the study analyses the effects on crack repair material, reveals the relation between the microstructure and macroscopic property of material. Finally, the study recommendes the cement concrete pavement micro-crack repair material which can meet every requirement of road properties.