Behaviour of Flexible Pavements: A Comparativ...

Behaviour of Flexible Pavements: A Comparative Study by Using FWD and IITPAVE Software

Author Name : Pratip Das, Rajkumar Banarjee, Abhipriyahalder, Sibapriya Mukherjee

ABSTRACT

This paper evaluates and compares the deflection of flexible pavement using two methods: The Falling Weight Deflectometer (FWD) test and IIT-Pave software. The data for the project road NH-129 (Numaligarh to Khatkhati) in Assam is utilized for the current investigation. The subgrade modulus and the pavement thickness are obtained from the FWD result and the trial pit data, respectively. These values are then used to calculate the deflection of flexible pavement using IIT-Pave software. Two types of loading are considered for the calculation of deflection values: 20 kN with the dual wheel and 40 kN with the single wheel. The results of the study reveal that the deflection values calculated from IIT-Pave software are on average 22% and 5% lower than the FWD results for 20 kN dual wheel loading and 40 kN single wheel loading, respectively. During the calculation of deflection values, horizontal tensile strain and vertical compressive strain is also determined for above mentioned two types of loading. The result reveals than the tensile strain values for 40 kN single wheel load are average 8% more than strain values for 20 kN dual wheel load for bituminous layer thickness more than 60mm. And where the bituminous layer is around less than 60mm, strain values for 40 kN single wheel load are average 9% less than strain values for 20 kN dual wheel load. Further for compressive strain, it is average 21% more for 40 kN single wheel than 20 kN dual wheel load. In case of growth of traffic, considering good pavement condition overlay design has been done for first 13 km stretch for different traffic. From the overlay design, it is found that, for increasing of each 10 MSA traffic, there is an increase of around 50mm bituminous overlay thickness. These findings provide insight into the reliability and accuracy of IIT-Pave software for assessing the deflection of flexible pavements and emphasize the importance of selecting appropriate loading conditions for obtaining accurate deflection measurements.

Keywords: Deflection; FWD Test; IIT-Pave, Flexible Pavement