To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt m...To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt material performance tester AMPT .In order to evaluate the validity of the proposed fracture test four different loading rates including 1 2 3 and 4 mm/min are examined in the AMPT. The results indicate that the fracture behavior is similar to creep at a low loading rate and does not show significant marginal tail extension at a high loading rate.It clearly shows the phase of crack initiation crack propagation and fracture at a loading rate of 3 mm/min. Besides eight fracture parameters such as fracture energy tensile strength and tensile modulus are applied to evaluate the fracture characteristics of asphalt mixture.Development of the overlay tester for the fracture test of asphalt mixture can be considered as a new fracture test of asphalt mixture.展开更多
A hot-mix asphalt(HMA) overlay is one of the primary strategy for rehabilitating existing HMA pavements and Portland cement concrete(PCC) pavements. The current design program, FAARFIELD, does not address reflective c...A hot-mix asphalt(HMA) overlay is one of the primary strategy for rehabilitating existing HMA pavements and Portland cement concrete(PCC) pavements. The current design program, FAARFIELD, does not address reflective cracking for asphalt-overlaid concrete pavements due to its mechanism complexity. The bending, shearing, and thermal are three crucial factors to successfully model reflective cracking. To implement this failure mode in flexible over rigid design procedure, a series of full-scale test pavements were constructed, instrumented, and tested in the condition of extreme cooling temperature at the FAA National Airport Pavement Test Facility. The purpose was to assess cooling effects on the propagation of reflection cracks for airport AC over PCC pavements. In preparation for reflective cracking phase VI test, the FAA is conducting laboratory experiment on field extracted hot mix asphalt(HMA) cores. In order to test these field HMA cores, the Texas Overlay Tester(OT) was customized to get data similar to the full-scale tests. This paper discusses finite element analysis on the full-scale testing, development of the customized Texas OT, and a laboratory testing suite using the customized Texas OT, including preliminary tests, instrumentation, experiment design, and test results. Data obtained from this research effort will be used to develop a rational testing procedure to simulate extreme cooling cycles through full-scale testing.展开更多
基金The National Natural Science Foundation of China(No.51178114)the Chinese Western Transportation Construction Technology Project of Transportation Ministry(No.2009318000086)
文摘To determine the fracture characteristics of asphalt mixture a novel fracture test with modified loading modes loading fixtures and the control system of the conventional overlay tester is implemented by the asphalt material performance tester AMPT .In order to evaluate the validity of the proposed fracture test four different loading rates including 1 2 3 and 4 mm/min are examined in the AMPT. The results indicate that the fracture behavior is similar to creep at a low loading rate and does not show significant marginal tail extension at a high loading rate.It clearly shows the phase of crack initiation crack propagation and fracture at a loading rate of 3 mm/min. Besides eight fracture parameters such as fracture energy tensile strength and tensile modulus are applied to evaluate the fracture characteristics of asphalt mixture.Development of the overlay tester for the fracture test of asphalt mixture can be considered as a new fracture test of asphalt mixture.
文摘A hot-mix asphalt(HMA) overlay is one of the primary strategy for rehabilitating existing HMA pavements and Portland cement concrete(PCC) pavements. The current design program, FAARFIELD, does not address reflective cracking for asphalt-overlaid concrete pavements due to its mechanism complexity. The bending, shearing, and thermal are three crucial factors to successfully model reflective cracking. To implement this failure mode in flexible over rigid design procedure, a series of full-scale test pavements were constructed, instrumented, and tested in the condition of extreme cooling temperature at the FAA National Airport Pavement Test Facility. The purpose was to assess cooling effects on the propagation of reflection cracks for airport AC over PCC pavements. In preparation for reflective cracking phase VI test, the FAA is conducting laboratory experiment on field extracted hot mix asphalt(HMA) cores. In order to test these field HMA cores, the Texas Overlay Tester(OT) was customized to get data similar to the full-scale tests. This paper discusses finite element analysis on the full-scale testing, development of the customized Texas OT, and a laboratory testing suite using the customized Texas OT, including preliminary tests, instrumentation, experiment design, and test results. Data obtained from this research effort will be used to develop a rational testing procedure to simulate extreme cooling cycles through full-scale testing.
