| The main pavement material of our country highway is asphalt mixture. Because the early disruption of asphalt pavement is serious, it need to be maintained timely. The overlay treatment is a common maintenance. Asphalt overlay adopts the hot asphalt mixture, the micro-surfacing and the Nova chip ultra-thin wearing course, etc., but don’t satisfy the requirement of "energy conservation, environmental protection and low carbon emissions". On the basis of consulting a large number of references at home and abroad, this paper proposes a new type of cold asphalt mixture for ultra-thin overlay. It has low noise, high driving comfort, good anti-sliding performance, high safety, low comprehensive cost, extended construction season, low environmental pollution, etc., and expects that have broad prospects in the use of pavement maintenance.Strength and water stability of asphalt mixture are the most critical properties for the cold ultra-thin overlay. This paper introduces the formation mechanism of strength and adhesion theory of water stability and their own test and evaluation method aiming at these two theories.After selecting the raw material and using the planning method to get the proportion of mineral mixture, we get the best dosage of mineral powder, the best matrix asphalt content, the best gradation and the best proportion of cold asphalt mixture for ultra-thin overlay by Modified Marshall test and Immersion Marshall Test.According to the cold asphalt mixture for ultra-thin overlay under normal condition and simulate condition in good health, we can use Freeze-thaw Splitting Test, Rutting Test and Trabecular Bending Test to verify the good results of water damaging resistance, high temperature stability and low temperature crack resistance for cold asphalt mixture for ultra-thin overlay.Finally, this paper expounds the suggestion of production, storage, construction technology, quality control and project acceptance. It has some guiding significance for the follow-up. |
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