Evaluation On Long-term Performance Of Cold Mixed Asphalt Pavement

Compared with Hot Mixed Asphalt(HMA),Cold Mixed Asphalt(CMA)has the advantages of energy-saving,less pollution,convenient in construction.Moreover,it possesses a strong adaptability to the surrounding environment,can be act as a kind of quick repair production and so on.CMA will be a tendency of road material in the future.This paper aims to learn about the long-term performance of CMA based on self-developed Emulsion,including fatigue performance,moisture sensitivity and resistance to aging and chemical corrosion.The performance of emulsion-based CMA is closely related to the condition of curing.Therefore,the effects of natural curing and oven curing in the laboratory on performance were compared with one-way analysis of variance and difference analysis.Results show that CMA samples' Marshall Stability,residual stability,water stability,low and high temperature performance which was cured in 90? for 24 h are similar to samples which were cured naturally.Therefore,the condition of curing is sent at 90? for 24 h in later testing.Firstly,fatigue properties of CMA is evaluated by four-point bending load beam fatigue test.Fatigue tests of a single-stage load and multi-level amplitude load are under four kinds of strain levels(200???400???600???800??).The fatigue function of single-stage loading is modeled,which can be described with strain and stiffness modules.The model to predict the life are evaluated in CMA under multi-level amplitude loadingSecondly,the CMA's resistance to moisture damage is evaluated.Freeze-thaw splitting test are used to evaluate the resistance to water damage of CMA under the influence of stilling water.With the help of industrial CT,sectional views can be got during freezing and thawing processes and they are transformed to be 2D&3D structural image models by MATLAB.On microscopic level,it is revealed the reason of CMA cleavage strength loss.In addition,immerse rutting tests are used to evaluate the resistance to water damage of CMA under the influence of moving water.Thirdly,the CMA's anti-aging properties was evaluated.In terms of photoaging aging,the relationship between photoaging time and CMA's performance was simulated by Verhulst biological model.The photoaging rate and photoaging acceleration are acquired.In terms of thermal oxygen aging,CMA were subjected at 85 °C,and 10 cycles were observed in 7 days as a cycle.The results shows that photoaging had a great influence on the low temperature CMA performance and thermal oxygen had a significant influence on the water damage.Finally,the CMA's resistance to chemical was evaluated.In terms of the chemical corrosion by snow melting agent,the damage degree is used to evaluate the attenuate performance by NaCl,NC,CaCl2 solution.The results shows that NaCl snow melting agent had the greatest influence on CMA,followed by NC,and CaCl2 had the least influence.In terms of the chemical corrosion by acid rain,the sulfuric acid solution is to simulate the corrosion of CMA by acid rain.The results shows that acid rain had the greatest damage to CMA stability.