Fabrication And Performance Of Novel Cold-mix Asphalt Mixture

Nowadays our road is based on hot-mix asphalt mixture,which is widely applied because of its excellent properties.But there are still some problems with it,such as high construction temperature,large energy consumption,great damage to the environment,etc.Meanwhile hot-mix asphalt mixture has a high request on construction season.For this reason,cold-mix asphalt mixture arises with advantages of energy conservation,environmental protection,low construction conditions.However,cold-mix asphalt mixture's pavement performance is inferior to hot-mix asphalt mixture's,especially in mechanical properties,which greatly limits the application of cold-mix asphalt mixture.The binder based on CA mortar is improved to prepare a novel cold-mix asphalt mixture.This paper investigates binder formula,preparation technology,maintenance condition,properties to fabricate a novel cold-mix asphalt mixture.Also the paper studies the effcet of mixture's component and ratio on mechanical properties and analyzes the strength formation mechanism.The paper studies the effect of asphalt–cement ratio and sand–cement ratio on the binder's properties.The test results show that reducing asphalt–cement ratio of binder,fluidity performance gets better,flexural strength and compressive strength increase,but the ratio of bending-compressive strength decline.With the increase of sand-cement ratio,flexural strength and compressive strength decline,however,fluidity performance has little change.Through the investigation,the optimized formula of binder is as follows: asphalt–cement ratio is 0.85 and sand-cement ratio is 1.the dosage of binder is 17% of aggregate;The optimized preparation technology is as follows : first the binder is prepared,then it will be mixed with aggregate and mineral powder.Maintenance condition is designed as follows: after 24 hours' curing under 60?,knockout samples will be put in maintenance oven under 25?,the maintenance time is 3 days,7 days and 28 days.The test results of cold-mix asphalt mixture show that mechanical property of cold-mix modified asphalt mixture is much higher than cold-mix base asphalt mixture's.As for base asphalt,the lower grade,the mechanical property is higher.With the same penetration level,asphalt from different oil source has little effect on mixture's mechanical property.It is beneficial for cold-mix asphalt mixture's mechanical property to reduce asphalt–cement ratio and sand-cement ratio.Through the correlation study of binder's mechanical property and cold-mix asphalt mixture's,it has good linear correlation between them.Mechanical properties of cold-mix asphalt mixture can be predicted through binder's properties.By DMA,cold-mix asphalt mixture has lower modulus in low temperature and higher modulus in high temperature compared to hot-mix asphalt mixture.By analysis of pavement performance,compared to hot-mix asphalt mixture,cold-mix asphalt mixture has better high-temperature stability,stronger ability to resist water damage,but has worse splitting strength.The paper also analyzes the strength formation mechanism of cold-mix asphalt mixture.The strength of cold-mix asphalt mixture mainly comes from interlocked-denseness of coarse aggregate and sand,inner friction resistance and the cohesive force of asphalt cement and cement hydration products.