道材第三章作业答案道材第三章作业答案.docVIP

Temperature (℃) 15 25 Penetration () Specimen A 50 95 Specimen B 51 70 There are two kinds of asphalt specimen A and B. If their penetration test results under different temperature show in following table, explain what is each specimen characteristic on temperature susceptibility and indicate which one is preferred in hot weather condition. Solution: Specimen A: Specimen B: As the bigger PI,the smaller temperature susceptibility, so Specimen A has better temperature susceptibility. B is preferred in hot weather condition. Discuss the aging that occurs in the asphalt cement during mixing with aggregates and in service. How can the different types of aging of asphalt cement be simulated in the laboratory? Solution: (1)、The aging during mixing with aggregates is short-term aging. The aging in service is long-term aging. (2)、for short-term aging：TFOT(薄膜烘箱加热试验）、RTFOT（旋转薄膜烘箱加热试验） for long-term aging：PAV（压力老化试验） Addition: After aging ,penetration decrease, viscosity increase, ductility decrease, softening point increase, mass may decrease or increase. Show how various Superpave tests used to characterize the asphalt binder are related to pavement performance? Solution： (1)Aging test老化试验-------Durability RTFOT ：for short-term aging PAV：for long-term aging Rotary viscosimeter （旋转式粘度计）------- Viscosity measure viscosity of asphalt (3)Dynamic Shear Rheometer （动态剪切流变仪）-----Visco-elastic Determination of viscoelastic properties of asphalt within temperature at 5-85℃ before and after aging, and also presentation the ability for anti-rutting at high temperature condition (4) Direct Tension Test（直接拉伸仪）-----Low temperature property Evaluation of asphalt material performances at low temperature, such as stress and strain when destruction, especially to evaluate the performances for polymer modified asphalt. (5)Bending Beam Rheometer （弯曲梁流变仪）------Low temperature property Measurement accurately of stiffness at low temperature and creep ra