Numerical Simulation Ansysis On The Expansion Of Vertical Cracks In Asphalt Pavement

Asphalt pavement has many Advantages,such as formation surface, without joints,driving comfort,wear-resistant rub,small vibration,low noise,short construction period,simple maintenance and suitable for construction in phases, etc. So at home and abroad a number of high-grade highway asphalt type surface forms has been adopted .Asphalt pavement has become the main types of road pavement. However, asphalt pavement and more common and complex diseases. A variety of reasons which lead to cracks in the asphalt pavement is an early one of the main forms of damage. The people have been aware of cracks in roads into the following four typical patterns: (a)fatigue crack,(b) reflective crack,(c)low-temperature cracks, (d)the expansion of the vertical cracks. Domestic and foreign scholars and staff of road fatigue cracks in low-temperature cracking and reflective cracking has been done more research and evaluation,also made a fairly complete results. However,in recent years, with the development of transport, vertical cracks in asphalt pavement caused by damage to the roads have become increasingly prominent. This problem has begun to attract domestic and foreign road workers more and more attention.Therefore,this article mainly on asphalt pavement structure of the study, the use of fracture mechanics theory, from the traffic load, road structure parameters, the depth of cracks in different perspectives, research analysis of longitudinal cracks in asphalt pavement to expand the law of the road for the future design, construction and maintenance to provide a reference,has an important practical significance.The full text includes five chapters. The first chapter discusses the research background and significance, both at home and abroad on different types of road crack research methods, results.Because of vertical cracks in asphalt pavement due to the expansion of the current status of the study less, so the authors advanced the main task this paper.Chapter II, from the basic concepts of fracture mechanics approach, introduced the basic types of cracks, the singularity of crack tip stress field and displacement field, the judge theory based on crack-related complex. Chapter III, first of all, combined with the engineering characteristics of asphalt pavement, the author use the finite element software model of the road to budget the sizes. then the author successly continued to introduced a singular unit, to establish a three-dimensional model of asphalt pavement withVertical cracks. Finally, the authors used the standard three-point bending test specimen to verify the two different calculation methods. By comparing the obtained results, the author obtained the result that J integral method results more precise. Chapter IV, first of all,the authors calculated the stress distribution of the road with traffic load. And the anthor came to the conclusion that vertical cracks in asphalt pavement is the direct cause of the shear stress caused by car, rather than tensile stress. Based on traffic load, the depth of cracks in the road structure parameters as variables .The author calculated and analysed the change of crack tip intensity factor, pointed out the law that the vertical cracks expand in asphalt pavement. Chapter V,the author summarizes the content of the full text. he also pointed out that the next step needs to improve and add content.