Evaluation on Low Temperature Cracking Resistance of Asphalt Mixture Based on SCB Test at Different Temperatures
In order to enhance the convenience and precision of evaluating the low temperature cracking resistance of asphalt mixtures,an investigation into the rationale behind the increase in fracture energy with rising temperature is undertaken through an analysis of the fracture energy components of the SCB test.A method for computing the viscous dissipative energy of asphalt mixture based on the SCB test is proposed and employed for the assessment of the low temperature cracking resistance of asphalt mixtures.The low temperature cracking resistance of 6 asphalt mixtures is examined and appraised through the design of SCB tests.The result shows that(1)The escalation of fracture energy in the asphalt mixture with increasing test temperature is primarily attributable to the rise in viscous dissipation energy.(2)The SCB test is utilized to estimate the viscous dissipation energy of the asphalt mixture for the evaluation of low temperature cracking resistance.By utilizing the viscous dissipative energy as the assessment indicator for low temperature cracking resistance and comparing the change amplitude of the viscous dissipative energy of different recycled asphalt mixtures.It is observed that the maximum change amplitude(the difference between AC20R40 and AC20R40RA test groups)reaches 72.2%,which significantly surpassing the change amplitude of the fracture energy.This approach effectively distinguishes the low temperature cracking resistance of different reclaimed asphalt mixtures and mitigates the influence of test errors on evaluation results.(3)With the increase of test temperature,the asphalt mixture transitions gradually from brittle failure to ductile failure,leading to a reduction in the aggregate fracture area on the fracture surface and increased molecular agitation,resulting in a gradual decrease in the surface energy of the asphalt mixture.Consequently,the observed pattern of fracture energy increasing initially and then decreasing with temperature is attributed to the influence of viscous dissipation energy.The temperature corresponding to the peak point of fracture energy aligns with the temperature at the peak point of viscous dissipation energy.(4)It is recommended that the viscosity dissipation energy is calculated based on the difference in fracture energy from SCB tests conducted at ―12℃and 0℃to evaluate the low temperature cracking resistance of asphalt mixtures.
road engineeringasphalt mixtureSCB testlow temperature cracking resistanceviscous dissipation energyperformance evaluation
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