| With the rapid development of the national economy in recent years,the construction of domestic highways has also been developed rapidly.Due to the excellent road performance of asphalt concrete,it is the main and most commonly used layer material for high grade highway in our country.Asphalt surface in the process of serving directly exposed to the natural environment,while being long-term weathering,freezing rain and vehicle load repeatedly function,and frequently,rutting of asphalt road surface,polished surface functions such as attenuation of early damage,seriously affected the driving comfort and safety.And ultrathin skin coat is now more common and effective pavement maintenance maintenance plan,but now the ultrathin skin coat of hot mix asphalt mixture are used for construction,and construction conditions of hot mix asphalt mixture is strict,only under the condition of suitable climate construction can play a good effect.In many bad conditions,therefore,the disease of pavement can’t get timely repair,and under the influence of ecological crisis,road in the road engineering is emphasizing infrastructure and common development of environmental protection and sustainable development.Cold mix asphalt mixture with environmental protection and energy saving,low temperature,the advantages of convenient operation,so the cold mix asphalt mixture used in ultra-thin surface technology will have larger significance and feasibility.But common cold mix asphalt mixture as a structure layer may lead to some problems,the main problem is in the shape of the early strength is low,and needs a long process to achieve the final strength,this feature is also greatly hinder the development of cold mix ultra-thin asphalt mixture.Therefore,it is very important to improve the early strength of the mix materials of cold mix.In this paper,combining with the characteristics of cold mix ultra-thin asphalt mixture,early strength at home and abroad for reference,the evaluation method of grinding wheel to load test method of forming die was improved,and put forward a kind of more suitable for evaluation of cold mix ultra-thin asphalt mixture of early strength test method.Then select Novachip Type B,UTAC-10,the SMA-10 three typical slim finish grading,through modified Marshall test method,respectively,to determine the three types of grading on the optimum proportion,and the proposed evaluation method to compare the three kinds of grading does not add any additives in case forming early strength of the specimens,the results show that the Novachip grading Type B than the other two gradation is more suitable for applications with cold mix ultra-thin asphalt mixture.After selecting the appropriate grading,this paper studies its effect of improving the early strength of mixed asphalt mixture by adding different measuring additives.Experimental results show that SBR latex,cement,epoxy resin and other additives can significantly improve the early strength of cold mix ultra-thin asphalt mixture,and to the late strength also to have certain improvement effect,among them,the improvement of the epoxy resin effect is best;But in the economy and the operability of construction into consideration,additive measurement is not the more the better,but in the case of right amount can exert the best effect.Finally,to add additive cold mix ultra-thin asphalt mixture in the high temperature stability,low temperature stability and water stability performance verification,including improved cold mix ultra-thin high temperature stability and water stability of asphalt mixture were improved,and meet the specification requirements;But the low temperature performance,in addition to add SBR latex after improved and can meet the specification requirements,adding cement and low temperature performance did not improve the effect of epoxy resin mixture,so this article suggest to take other measures to separate to improve low temperature performance. |
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