Study On The Performance Of Self-Compacting Concrete For Large Cracks Repair In Cement Pavement In Cold Areas

Cement concrete pavement are apt to damages in cold regions under the effect of traffic load and natural conditions, and the crack is one of the most important damage forms. It is necessary to repair the cracks timely and effectively in order to extend the service life of the pavement. Asphalt and epoxy are the most commonly used materials in pavement cracks repair at present, but they have some defects such as high costs, easy to aging, and not environmentally friendly. Combined with the climate characteristics in cold areas, polymer modified self-compacting concrete is used to repair the cracks wider than15mm in this paper, aiming to develop a kind of repair material for cracks in concrete pavement which is easy to construction, cheap, environmentally friendly, and has a good workability.The method of fixing volume of sand and gravel is used in this paper for the mix design of self-compacting concrete. The influence law of parameters such as water-binder ratio, total cementitious materials, content of fly ash and sand percentage on properties of the self-compacting concrete are analyzed. On this basis, styrene-butadiene emulsion and styrene-acrylic emulsion are used to modify the self-compacting concrete respectively, and the polymer cement ratio are chosen as1%,3%,5%,8%,10%, and15%respectively, then the workability, mechanical properties, bonding properties and durability of different self-compacting concrete are researched through experiments. The influence of polymer on the microstructure of the self-compacting concrete is analyzed through SEM tests in the last.The results show that the workability of the self-compacting concrete mixture is best when the water-binder ratio is0.41, total cementitious materials is460kg/m, content of fly ash is30%and sand percentage is49%, and the workability is better when the shape index of the coarse aggregate is bigger. The addition of the polymer to the self-compacting concrete improves the flexibility, interfacial bond property, and durability of the self-compacting concrete. In the microscopic aspect, continuous polymeric membrane is formed in the concrete after the addition of polymer, and the pores are refined, and dense spatial wire mesh-like skeleton structure is formed, so the macroscopic properties of the self-compacting concrete are improved. After a comprehensive analysis, styrene-butadiene emulsion modified self-compacting concrete performs better as the cracks repair materials when the polymer cement ratio is10%. Styrene-butadiene emulsion polymer modified self-compacting concrete is suitable for the repair of large cracks in the cement concrete pavement of rural highway in cold regions.