Low-temperature Cracking Resistance of CR Composite Modified Asphalt by Physical Hardening
It is important to study the change rule of low-temperature cracking resistance of crumb rubber composite modified asphalt(CRMA)materials before and after physical hardening to improve the quality of highway projects in cold regions.In this paper,the influence mechanism of physical hardening on the low-temperature cracking resis-tance of CRMA was investigated by the single-edged notched beam(SENB)test.Asphalt samples had been kept at constant temperature in anhydrous ethanol solution at-12 ℃,-18 ℃ and-24 ℃ before the test,respectively for 1 h,12 h,24 h,36 h and 48 h to simulate different physical hardening of the asphalt.The results show that the decrease of low-temperature cracking resistance of modified asphalt after 24 h of constant temperature is gradually steady,and the physical hardening tends to be saturated;The physical hardening level of modified asphalt show normal dis-tribution with the reduction of temperature,while not the lower the temperature,the more serious physical harden-ing;The physical hardening level of modified asphalt is the largest at-18 ℃;The physical hardening resistance of SBS modified asphalt(SBSMA)is better than CRMA.However,low-temperature cracking resistance of CRMA is much better than SBSMA before and after physical hardening,which is more suitable for highway engineering in cold region;The fracture energy index based on the SENB test at constant temperature for 24h is recommended to char-acterize the low-temperature cracking resistance of modified asphalt materials in cold regions.
万方数据
维普
