Based on four-year field inspection and investigation on deck pavement of mastic asphalt on Jiangyin Bridge, cracking causes of mastic asphalt are studied. Cracks of deck pavement are summarized on crack length and wi...Based on four-year field inspection and investigation on deck pavement of mastic asphalt on Jiangyin Bridge, cracking causes of mastic asphalt are studied. Cracks of deck pavement are summarized on crack length and width to get a clear view of their propagations. Traffic surveys including traffic volume, axle load and vehicle speed were also conducted to assess their influences. Samples taken on-site were tested with pulling-out test and fatigue test to benchmark their properties. According to the inspection and tests results, it is concluded that the cracks are induced by rutting and fatigue. Lack of fatigue resistance, not well bonded to the steel deck and insufficient high temperature stability are supposed to be the main reasons as well as high density of low speed, excessively overloaded trucks.展开更多
The mix design method of asphalt rubber open-graded friction course (AR-OGFC) by the Marshall test and key technologies of AR-OGFC overlay are studied. Based on the draindown test, the stripping test and the Marshal...The mix design method of asphalt rubber open-graded friction course (AR-OGFC) by the Marshall test and key technologies of AR-OGFC overlay are studied. Based on the draindown test, the stripping test and the Marshall test by different beating times, the asphalt content estimating method and Marshall beat criterion are studied. It is found that the asphalt content of AR-OGFC can be estimated by the formula of Arizona, and the proper Marshall test criterion for AR-OGFC is 50 beats on both sides. By analyzing the influence of gradation on OGFC performance, the gradation of AR-OGFC is recommended, and the amount of aggregate passing 4. 75 mm should be minimized for AR-OGFC. Through investigation of AR-OGFC overlay projects, key technologies such as the treatment of underlying pavement and the selection of tack coat are advanced, and modified emulsified asphalt should be used in AR-OGFC overlay tack coat.展开更多
Field cores from typical cracking locations were tested by the semi-circular bending test and the digital image correlation method to evaluate the anti-fatigue performance of different asphalt pavements. Test results ...Field cores from typical cracking locations were tested by the semi-circular bending test and the digital image correlation method to evaluate the anti-fatigue performance of different asphalt pavements. Test results were analyzed by different fatigue models. Causes of fatigue cracking for different pavement sections were determined by extraction and sieving test results. It is found that the ranking (from high to low) in terms of the anti-fatigue performance for field cores is the crumb rubber modified asphalt mixture, densegraded modified asphalt mixture, continuous graded asphalt treated base, gap-graded stone asphalt concrete, and half open-graded asphalt macadam. Compared with the half opengraded asphalt macadam, the fatigue life of the crumb rubber modified asphalt mixture improves by 2. 0 to 3. 8 times. Fatigue lives of different mixtures and distress ratios of actual pavements can be accurately predicted by the dissipated energy density ratio. Causes of fatigue cracking vary with mixture types.展开更多
文摘Based on four-year field inspection and investigation on deck pavement of mastic asphalt on Jiangyin Bridge, cracking causes of mastic asphalt are studied. Cracks of deck pavement are summarized on crack length and width to get a clear view of their propagations. Traffic surveys including traffic volume, axle load and vehicle speed were also conducted to assess their influences. Samples taken on-site were tested with pulling-out test and fatigue test to benchmark their properties. According to the inspection and tests results, it is concluded that the cracks are induced by rutting and fatigue. Lack of fatigue resistance, not well bonded to the steel deck and insufficient high temperature stability are supposed to be the main reasons as well as high density of low speed, excessively overloaded trucks.
文摘The mix design method of asphalt rubber open-graded friction course (AR-OGFC) by the Marshall test and key technologies of AR-OGFC overlay are studied. Based on the draindown test, the stripping test and the Marshall test by different beating times, the asphalt content estimating method and Marshall beat criterion are studied. It is found that the asphalt content of AR-OGFC can be estimated by the formula of Arizona, and the proper Marshall test criterion for AR-OGFC is 50 beats on both sides. By analyzing the influence of gradation on OGFC performance, the gradation of AR-OGFC is recommended, and the amount of aggregate passing 4. 75 mm should be minimized for AR-OGFC. Through investigation of AR-OGFC overlay projects, key technologies such as the treatment of underlying pavement and the selection of tack coat are advanced, and modified emulsified asphalt should be used in AR-OGFC overlay tack coat.
基金The National Natural Science Foundation of China(No.51308303)the Natural Science Foundation of Jiangsu Province(No.BK20130980)+1 种基金Qing Lan Project,the Practice Innovation Training Program Projects for the Jiangsu College Students(No.201410298024Z)the Scientific Innovation Research of College Graduates in Jiangsu Province(No.SJLX15_0418)
文摘Field cores from typical cracking locations were tested by the semi-circular bending test and the digital image correlation method to evaluate the anti-fatigue performance of different asphalt pavements. Test results were analyzed by different fatigue models. Causes of fatigue cracking for different pavement sections were determined by extraction and sieving test results. It is found that the ranking (from high to low) in terms of the anti-fatigue performance for field cores is the crumb rubber modified asphalt mixture, densegraded modified asphalt mixture, continuous graded asphalt treated base, gap-graded stone asphalt concrete, and half open-graded asphalt macadam. Compared with the half opengraded asphalt macadam, the fatigue life of the crumb rubber modified asphalt mixture improves by 2. 0 to 3. 8 times. Fatigue lives of different mixtures and distress ratios of actual pavements can be accurately predicted by the dissipated energy density ratio. Causes of fatigue cracking vary with mixture types.