Reasonable thickness of asphalt layer in graded crushed stone base asphalt pavement(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年04期
- Page:
- 1-9
- Research Field:
- 道路工程
- Publishing date:
Info
- Title:
- Reasonable thickness of asphalt layer in graded crushed stone base asphalt pavement
- Author(s):
- HAN Zhenqiang; SHA Aimin; HU Liqun; LIU Zhuangzhuang
- 1. School of Highway, Changan University, Xian 710064, Shaanxi, China; 2. Key Laboratory for Special Area Highway Engineering of Ministry of Education, Changan University, Xian 710064, Shaanxi, China)
- Keywords:
- road engineering; asphalt layer thickness; accelerated load testing; pavement design software; graded crushed stone base asphalt pavement
- PACS:
- -
- DOI:
- -
- Abstract:
- In order to investigate the reasonable asphalt layer thickness for graded crushed stone base asphalt pavement, BISAR 3.0 program was adopted to calculate the strain at the surface and bottom of different asphalt layer thickness, the compressive strain on the top of the subgrade, the shear stress of different depth in the asphalt layer and graded crushed stone base when the thickness of base was 20 cm and the thickness of asphalt layer range was 4 to 36 cm. The fatigue cracking, permanent deformation and rutting distress on the graded crushed stone based asphalt pavement of different asphalt layer thickness were determined according to fatigue limit stress of different structural layer. And the optimization of the asphalt layer thickness was realized according to the usability and durability of pavement structure. In order to verify the mechanical response and longterm performance of the graded crushed stone based pavement structure of thin asphalt layer, the fullscale accelerated pavement testing (APT) was used to verify the calculation of mechanical response, longterm performance and disease characteristics of the 5 cm asphalt layer pavement structure. The results show that when the thickness of graded crushed stone base is 20 cm, the asphalt layer should not be too thin, and when the thickness of the asphalt layer is less than 5 cm, the permanent deformation of the road surface and the fatigue cracking from top to bottom are easy to occur. The pavement is more prone to experience excessive permanent deformation and fatigue cracking when the asphalt layer thickness is less than 5 cm. When the asphalt layer thickness ranges from 5 to 18 cm, there is an unfavorable combination of large tensile strain on the bottom of asphalt layer, compressive strain on the top of subgrade, and maximum shear stress in the asphalt surface layer and the graded crushed stone base. The requirement of the perpetual asphalt pavement can be satisfy when the asphalt layer thickness is more than 34 cm, noticeably, the asphalt layer thickness should not be less than 18 cm when conditions are limited. APT test results illustrate that the calculation results of tensile strain at the bottom of the asphalt layer and the shear stress of the pavement structure basically conform to the actual service conditions of the test road. The main diseases of the pavement structure are rutting distress and permanent deformation, and fatigue cracking is not obvious. However, the calculated value of compressive stress at the top of the subgrade is too small, which should not be used as the design basis for the pavement structure. 2 tabs, 12 figs, 28 refs.
Last Update: 2018-08-03