Investigation on the Damaged Factors of Paving Asphalt Pavement

Chunhua Hu and Qiuhai Chen

Hubei University of Technology, Wuhan City, Hubei Province, China

Keywords: Pavement, Asphalt, Shearing force, Vertical deformation.

Abstract: Pavement has been a technical difficulty in road engineering. This paper compares the two pavement

schemes of modified asphalt mixture pavement and pouring asphalt pavement. Through the finite element

method simulation analysis, considering the influence of different parameters, we explore the relationship

between the stress value and deformation under different conditions. The analysis results show that

longitudinal shear stress is an important factor to destroy the road surface and affect the traffic.

1 INTRODUCTION

For a long time, road pavement has always been an

international research difficulties.Road pavement

materials not only greatly affected the normal use of

roads and the transportation function, but also plays

an extremely important role in traffic safety. In the

study of road pavement, the key problem lies in the

small surfacing layer stiffness and large

deformation, which requires good deformation of

asphalt pavement structure layer. At the same time,

the stress condition of the pavement is complex,

affected by temperature, in a larger horizontal shear

stress, the pavement layer shear displacement and

damage, appear easily affect the use and the traffic.

According to incomplete statistics, each year more

than billion yuan for the study of the road, of which

more than 35% is used in the pavement. At the same

time, the government to coordinate the area highway

construction in west China, the implementation of

the western traffic construction projects of science

and technology research has achieved fruitful

results.

2 PAVEMENT STRUCTURE AND

CHARACTERISTICS

Road pavement mainly refers to a layer of asphalt

mixture on the road surface layer, passing through

the asphalt mixture layer to transfer the force to the

lower base. Although it is based on the actual need

to choose different structure layer, but whatever the

form of pavement, generally can be divided into two

categories, namely waterproof (sometimes called

rust) system and body shop system (Wen, 2003).

The pavement plan is different from the actual

project. In the present stage, the asphalt pavement is

mainly modified with asphalt concrete and pouring

asphalt concrete (Ding, 2002). And the composition,

function and construction method of these two kinds

of pavement materials are very different from each

other.

2.1 Modified asphalt mixture paving

layer

In the early stage, due to lack of understanding of

modified asphalt mixture and pavement, there are

many diseases such as rutting, crack and passage in

road use. With the progress of materials and

technology, the comprehensive performance has

been improved greatly. The process of the paving

scheme is becoming more and more mature, and the

construction technology is simple, and it is used in

the municipal highway with small area and no

special requirement.

2.2 Casting asphalt concrete

The casting type asphalt concrete originated in

Britain, the main way of application of the pavement

in commonwealth countries .After the introduction

of our country, according to China's national

conditions, to adjust and optimize the structure and

material, formed the casting type pavement typical

structure. The scheme is the most commonly used in

our country, and the life is more than 12 years,no

matter from the late construction quality and

396

Hu, C. and Chen, Q.

Investigation on the Damaged Factors of Paving Asphalt Pavement.

In 3rd International Conference on Electromechanical Control Technology and Transportation (ICECTT 2018), pages 396-399

ISBN: 978-989-758-312-4

reliability maintenance. Compared with similar

schemes, it has obvious advantages, but also has its

corresponding faults, high temperature stability, easy

to form in at high temperature rut.

3 ANALYSIS OF STRESS

CHARACTERISTICS OF

ASPHALT PAVEMENT

Safety is the first requirement, we are in use in the

process of building surfacing with good

performance is the important guarantee of safe

driving vehicles, but a lot of road traffic within a

few years pavement layer occurs the problem such

as cracks, deformation, seriously affected the normal

use of roads and dramatically reduces the

transportation capacity.

Under the action of driving load, there are two

main ways to damage the pavement layer: first, the

internal damage is caused by the shear stress inside

the pavement layer, which causes the shear failure of

the paving layer. External damage mainly because of

pavement layer and layer panel joint surface

between the cohesive force is insufficient, weak

ability to resist horizontal shear, so prone to shear

displacement in horizontal direction, the final

package, goes on, beat on the pavement, as well as

the aging situation (Xu, 2002).

In this paper, based on the finite element

software ANSYS calculation, analysis of modified

asphalt mixture surfacing and the casting type

asphalt layer of internal force, when the maximum

shearing stress state, at the same time, considering

pavement changes related parameters, vehicle status

and level on the stress caused by different factors,

such as stress changing.

3.1 The influence of variation of each

parameter of asphalt concrete pavement

on the stress of pavement layer

In this paper, the influence factors of stress mainly

consider the thickness and elastic modulus of

pavement layer. In the design process of pavement,

an important index is to select the corresponding

structural layer according to the actual situation of

material and grade composition, and determine its

thickness (Luo, 1999). It is mainly due to the

particularity of asphalt concrete and the

non-uniqueness of asphalt concrete modulus. In the

process of development, asphalt concrete materials

are more and more functional, and different

materials are different in terms of modulus and

intensity. Secondly, even if the asphalt concrete

material is the same, the difference of temperature

and the time of loading will also affect the elastic

modulus. The change of elastic modulus will cause

the force change of the whole structure, and even to

another completely different stress equilibrium state.

And for the same material, because the modulus

changes with the temperature, the strength of the

material changes.

3.2 Relationship between thickness and

stress of pavement layer

In order to analyze the relationship between the

thickness of the modified asphalt mixture and the

structural stress, this paper uses the thickness of the

surface layer of 3cm, 5cm, 7cm, 9cm, 11cm,13cm

and 15cm.

(1) In the process of continuous change in the

thickness of the surface layer, the variation of the

main stress, normal stress and shear stress in the

surface layer is shown in table 1, and the

relationship curves of each stress and thickness are

shown in FIG. 1:

Table 1: variation of stress with thickness of modified asphalt mixture.

Thickness（cm）

σ1(Mpa) σx(Mpa) σz(Mpa) τxy(Mpa) τyz(Mpa)

3 0.6695 0.4459 0.6643 0.3216 0.3356

5 0.6385 0.4471 0.6355 0.2899 0.3043

7 0.5987 0.4143 0.6159 0.2829 0.2806

9 0.5876 0.3987 0.5998 0.2673 0.2525

11 0.5839 0.3597 0.5902 0.2643 0.2412

13 0.5789 0.3312 0.5832 0.2613 0.2388

15 0.5013 0.2896 0.5799 0.2195 0.1932

Investigation on the Damaged Factors of Paving Asphalt Pavement

397

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

3579111315

Stress

Thickness

σ1(Mpa)

σx(Mpa)

σz(Mpa)

τxy(Mpa)

τyz(Mpa)

Figure 1: The relationship between stress and

thickness

From table 1 and figure 1, it can be seen that in a

certain range, the greater the thickness of the

modified asphalt mixture pavement layer, the lower

the stress value in the asphalt concrete surface layer.

It can be seen that the thickness of pavement layer is

beneficial to the internal stress of the surface layer.

The longitudinal and vertical stress decreases, and

the transverse damping is larger. The transverse

shear stress decreases with the same thickness, and

the transverse shear stress is less than the

longitudinal shear stress.

(2) The main stress, normal stress and shear

stress vary with thickness as shown in table 2, and

the variation curve of relevant stress values and

pavement thickness is shown in FIG. 2.

Table 2: the value of the stress changes with thickness of asphalt concrete pavement.

Thickness（cm）

σ1(Mpa) σx(Mpa) σz(Mpa) τxy(Mpa) τyz(Mpa)

3 0.7369 0.3912 0.5437 0.1744 0.5593

5 0.6998 0.2846 0.4778 0.1621 0.4796

7 0.6801 0.2565 0.4553 0.1403 0.4611

9 0.6415 0.2312 0.4172 0.1279 0.4368

11 0.6032 0.2003 0.3889 0.1174 0.4098

13 0.5622 0.1933 0.3658 0.1076 0.3922

15 0.4936 0.1644 0.3422 0.0958 0.3503

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

3579111315

Stress

Thickness

σ1(Mpa)

σx(Mpa)

σz(Mpa)

τxy(Mpa)

τyz(Mpa)

Figure 2: The relationship between stress and

thickness

It can be seen from the above curve that in a

certain range, the longitudinal and transverse shear

stresses of the castable asphalt concrete pavement

are inversely proportional to the thickness. When the

stress is reduced, the decrease of longitudinal shear

stress is less than that of transverse shear stress. It

can be seen that increasing the thickness of the

pavement layer has a weak influence on the shear

stress. In practical application, the thickness of the

pavement layer should not be too large.

Other conditions by the above analysis we can

see that the same circumstances, with the gradual

increase of surfacing layer thickness, modified

asphalt mixture surfacing in lateral shear stress

change is higher than the change of shear stress in

the casting type concrete pavement layer. From table

1 you can see in table 2 casting type concrete

pavement layer of longitudinal shear stress is

significantly higher than the same conditions of

modified asphalt layer of longitudinal shear stress,

and modified asphalt pavement layer transverse and

longitudinal shear stress values gap is smaller.

4 CONCLUSION

On the basis of finite element simulation, the stress

analysis of pavement layer is carried out. The

maximum shear stress in two pavement layers and

the maximum vertical deformation of the pavement

layer are compared. Analyze the relationship

between these variables and draw the following

conclusions:

(1) Through the simulation analysis, it is shown

that the longitudinal shear stress is mainly used to

control the strength of the pavement when subjected

to both horizontal and vertical forces. Therefore,

longitudinal shear stress is the main factor that

damages the pavement layer, and is also the key

factor in traffic design.

(2) The stress in pavement layer is inversely

proportional to the thickness of asphalt layer in the

process of continuous change of pavement layer

ICECTT 2018 - 3rd International Conference on Electromechanical Control Technology and Transportation

398

thickness. The vertical deformation of asphalt

surface is proportional to the thickness of asphalt.

REFERENCE

Wen jingyun, research and destruction analysis of asphalt

concrete pavement [D]. Tianjin: hebei university of

technology, 2003, 10~25.

Ding qingjun, wang chuzhou, huang shaolong. Design of

pavement layer materials [J]. Journal of wuhan

university of technology.2002.24 (4).55~58.

Xu wei, li zhi, zhang xiao-ning. Experimental study on the

mechanical properties of concrete pavement bonding

layer system [J]. Journal of Harbin architecture

university. 2002,35 (4) :127.

Luo lifeng, zhong Ming, huang cheng. Summary of

concrete pavement [J]. Foreign highway, 1999, 19

(3): 23-26.

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