Modelling of Temperature Effects on Flexible and Rigid Pavements

Abstract

One of the most crucial elements impacting the rigid and flexible pavements performance is temperature. This significance necessitates specific care and interest in research to create design and analytical processes that take temperature issues into account. The variation in temperature is modelled using ANSYS v19.2 finite element method software. At any assigned depth in different layers of pavement, the stresses and deformation were obtained using solution of axisymmetric problem for an applied temperature of 45ºC. In flexible pavement the temperature stress variation was found to be 2.512 N/m² at top of bituminous concrete to 0 N/m² to the bottom of compacted subgrade layer, vertical deformation was found to be 0.013m at top of bituminous concrete to 0.0089m bottom of compacted subgrade layer. In the rigid pavement the temperature stress found to be 6.23 N/m² at top of concrete and-1.64 N/m² at bottom of subbase layer and horizontal deformation should be maximum and minimum of 0.0542m-0.0102m.

Introduction

I. INTRODUCTION

A. Flexible pavement     

In Pavement, that strength and deformation properties strongly depend on temperature. Therefore, in Flexible pavement design process enough attention has to be paid to correct determination of temperature in asphalt concrete layers. As the modern flexible pavement structures represent the multi-layer deformable media. Changes of deformations in asphalt concrete layers lead to change of stresses and deformations in other layers of pavement and subgrade. In practice, change of stresses and deformations in layers of pavement and subgrade, caused by temperature variation in asphalt concrete layers of pavement. It could be essential and should be taken into account at the design stage. Two-dimensional non-stationary problem of heat conduction for calculation of temperature in flexible pavement is solved by finite element method.

B. Rigid pavement

Temperature differential between the top and bottom of concrete pavements causes the concrete slab to curl, giving rise to stresses. The temperature differential is a function of solar radiation received by the pavement surface. As far as possible, temperature differential values estimated realistically for the given site using relevant geographical parameters and material characteristics should be used for analysis. Two-dimensional non-stationary problem of heat conduction for calculation of temperature in rigid pavement is solved by finite element method. If the maximum positive temperature differential during the day time is 20?C, the temperature differential for stress computation can be taken as 15?C. However, this 5?C reduction is generally not made so that the design for bottom-up cracking will be conservative.

C. Ansys Software

This chapter explains about the methodology carried out in this project work. In this project, to determine the temperature stresses and deformation in the flexible and rigid pavement by ANSYS v19.2 finite element analysis software. John Swanson developed the initial Ansys software. Ansys develops and markets engineering simulation software for use across the product life cycle. Ansys Mechanical finite element analysis software is used to simulate computer models of structures, electronics, or machine components for analyzing the strength, toughness, elasticity, temperature distribution, electromagnetism, fluid flow, and other attributes. Ansys is used to determine how a product will function with different specifications, without building test products or conducting crash tests. The paper uses transient thermal analysis method in ANSYS software to simulate the distribution of temperature changes between layers of pavement structure based on extreme temperature. Scholars at home and abroad have studied it.

II. NUMERICAL MODELLING OF FLEXIBLE PAVEMENT

Thus, to investigate this pavement near Hindustan Arts college was taken as reference. The pavement layers have totally 4, they are bituminous concrete, Wet Bound Macadam (WBM), Sub-base course, Subgrade having a thickness and the poisson’s ratio is taken from IRC 37:2019 code and the value for heat conductivity coefficient of each layer taken from [3] is shown in below Table 1:

IV. RESULTS AND DISCUSSION

Employed the finite element techniques to model flexible pavement using 3-D dimensional model with appropriate material characterizations and bonding conditions explained earlier in previous sections taking into consideration the effect of thermal loading due to high temperature occurred.

A. Analysis part of Flexible pavement

As can be seen from the figure 2, when the pavement temperature reaches 45°C, the heat flow vector direction is upward and the pavement is in an exothermic state. The temperature changes between layers are obvious, and the maximum temperature is at the surface layer. The vertical deformation was found to be 0.013m at 0m depth to 0.0089m at bottom of subgrade. When the pavement temperature is 450C, the heat release of pavement structure affects the pavement expansion. The surface temperature is positively correlated with time from 00 to 450C.

Temperature stress changes at top of bituminous concrete to the bottom of subgrade layer from 0 to 2.51 N/m2 at 45?C shown in below Fig 5. The greater the change of temperature, the greater the change of stress and deformation of flexible pavement. The optimum thickness keeps the temperature stress within a relatively low range.

Conclusion

In the Modelling of temperature effects in Flexible and Rigid pavement, The developed finite element model enables to calculate temperature in layered structure of pavement with high accuracy. From the applied of 45º C temperature causes significant change in their elastic modulus of the layered pavement. In Flexible pavement, stress variation due to temperature of top bituminous concrete to bottom subgrade layer is 2.512-0 N/m². The vertical deformation is 0.013m at top of bituminous concrete and 0.0089m at to bottom subgrade layer. In Rigid pavement, the temperature stress is distributed all across the model. Stress variation due to temperature of top concrete pavement to bottom sub-base layer is 6.23 N/m² to -1.63 N/m².The Total deformation is maximum of 0.0542m at top of concrete slab while minimum of 0.0102m at 32.5 cm of the sub-base layer.

References

[1] Bagdat Teltayev, Koblanbek Aitbayev.(2014) “Modelling of Temperature Field in Flexible Pavement”. Crossmark. [2] J. AntonioRamos García, MaríaCastro (2011) “Analysis of the temperature influence on flexible pavement deflection”. Construction and Building Materials. [3] Naiji Zhang, Guoxiong Wu, Bin Chen, Cong Cao (2019) “Simulation analysis on temperature field and temperature stress of flexible pavement in cold areas”. Journal of Applied Mathematics and physics. [4] Sameh S. Abd El-Fattah, Ahmed E. Abu El-Maaty and Ibrahim H. Hashim (2022) “Reliability Analysis of Flexible Pavement Using Crude Monte Carlo Simulation”. Engineering Research Journal. [5] Shrikant M. Harle1, Prakash S. Pajgade (2017) “ANSYS Workbench: Concrete Pavement Model”. International Journal of Modern Research in Electrical and Electronic Engineering.

Copyright

Copyright © 2023 S. Hariharan, S. P. Jeyapriya. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.