Damage Assessment for ME Rehabilitation Design of Modified Asphalt Pavements: Challenges and Findings

Author(s):  
Jhony Habbouche ◽  
Elie Y. Hajj ◽  
Peter E. Sebaaly ◽  
Nathan E. Morian

The overall objective of this study was to assess the use of Level 1 analysis for mechanistic-empirical (ME) rehabilitation designs of deteriorated polymer-modified asphalt concrete (AC) pavements in Nevada using the AASHTOWare® Pavement ME software. This research also explored the possible implementation of a hybrid approach for AC damage characterization to overcome the challenges associated with the use of the Witczak model for estimating the undamaged dynamic modulus master curve of the existing AC layer. Two rehabilitation field projects were used as part of this study. The experimental plan involved falling weight deflectometer (FWD) testing in the right wheelpath before rehabilitation, analysis of core samples, estimation of an equivalent undamaged dynamic modulus, and estimation of equivalent damaged dynamic modulus from FWD backcalculation. The proposed hybrid approach consisted of conducting laboratory dynamic modulus testing on the collected core samples and estimating an equivalent undamaged dynamic modulus at the same FWD testing temperature and loading frequency. The pre-overlay damage, characterized based on the approach in Pavement ME Design software (i.e., using a Witczak prediction model and backcalculated modulus), showed overly high values that did not match with the collected pre-overlay distress data on either of the rehabilitation projects. Based on the findings from this study, the hybrid approach was recommended for implementation by Nevada Department of Transportation (NDOT) when designing AC overlay over polymer-modified asphalt pavements in Nevada. Recommendations for user inputs were also provided for future consideration in Pavement ME Design software.

2015 ◽  
Vol 1113 ◽  
pp. 9-12 ◽  
Author(s):  
C.M. Nurulain ◽  
P.J. Ramadhansyah ◽  
A.H. Norhidayah

This paper presents a review of nanoclay as a latest technology in order to overcome problem due deterioration such as rutting, fatigue, stripping, cracking and so on. Nowadays, with increasing of traffic volume and heavy vehicle conditions of existing road totally fail in order to accommodate this situation during design period. In order to manage this problem the new technology had been create and apply. Previous researches prove that nanotechnology has potential solution to enhance the performance and durability of construction materials. Material properties were characterized using Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). According to previous research there were proved that addition of nanoclay lead great improvements on permanent deformation and fatigue life of hot mix asphalt (HMA). In addition the overall performance of nanoclay as polymer modified asphalt binder was improve in terms of rutting and fatigue cracking resistance compare to non-modified asphalt binder. Therefore, nanoclay itself would be an alternative as modifier to use in the bitumen to improve the lifetime of asphalt pavements.


2019 ◽  
Vol 9 (13) ◽  
pp. 2747 ◽  
Author(s):  
Hui Wang ◽  
Shihao Zhan ◽  
Guojun Liu

Asphalt migration is one of the significant detrimental effects on asphalt pavement performance. In order to simulate the state after the occurrence of asphalt migration amid asphalt pavement layers and further investigate the effects of asphalt migration on the dynamic modulus of asphalt mixture, samples with different asphalt contents layers were firstly separated into the upper and lower half portions and then compacted together. By conducting the dynamic modulus test with the Superpave Simple Performance Tester (SPT), the variation laws of the dynamic modulus (|E*|) and the phase angle (δ) at different testing temperatures and loading frequencies were analyzed in this paper. Further, the dynamic modulus and the stiffness parameter (|E*|/sinδ) at the loading frequency of 10 Hz and testing temperature of 50 °C were illustrated. Simultaneously, the master curves of the dynamic modulus and phase angle of asphalt mixtures under different testing conditions were constructed to better investigate the effects of asphalt migration on the dynamic modulus by means of Williams–Landel–Ferry (WLF) equation and Sigmoidal function. Results show that, after the asphalt migration, the dynamic modulus of asphalt mixtures increase with the increasing loading frequency while they decrease with the increasing testing temperature; the dynamic modulus and the stiffness parameter are the highest when asphalt mixtures have the optimum asphalt content layers, and then decrease with the incremental difference of asphalt content in the upper and lower half portions. Besides this, different from the master curves of dynamic modulus, the master curves of phase angle firstly increase with the increase of loading frequency to the highest point and then decrease with the further increase of loading frequency and are not as smooth as that of dynamic modulus. It can be concluded that the asphalt migration has compromised the mixture’s mechanical structure, and the more asphalt migrates, the weaker the mechanical properties of asphalt mixture will be. Additionally, based on the shift factors and master curves in the time–temperature superposition principle (TTSP), the effects of asphalt migration on the dynamic modulus and the variation laws of the dynamic modulus of asphalt mixture after the occurrence of asphalt migration can be better construed at the quantitative level.


Author(s):  
Jim Trepanier ◽  
John Senger ◽  
Todd Thomas ◽  
Marvin Exline

Many states are looking for methods to improve longitudinal joint performance of their asphalt pavements, since these joints often fail before the rest of the surface. With their inherently lower density, longitudinal joints fail by cracking, raveling, and potholing because of the intrusion of air and water. Because of their longitudinal joint issues, and after trying several less-than-successful traditional solutions, Illinois Department of Transportation (IDOT) developed a concept to seal the longitudinal joint region, but from the bottom up. Test sections were constructed in 2001 through 2003 to determine how a newly developed material, called longitudinal joint sealant (LJS), would improve joint performance. LJS is a highly polymer-modified asphalt cement with fillers and is placed at the location of a longitudinal joint before paving. As mix is paved over it, the LJS melts and migrates up into voids in the low-density mix, making the mix impermeable to moisture while sealing the longitudinal joint itself. The IDOT test pavements were evaluated after 12 years and found to have longitudinal joints that exhibited significantly better performance than the control joint sections and were in similar or better condition than the rest of the pavement. Laboratory testing of cores showed decreased permeability and increased crack resistance of mix near joints with LJS as compared with similar mix without LJS. The life extension of the joint area is approximately 3–5 years, and the benefit is calculated to be three to five times the initial cost.


2020 ◽  
Vol 2 (2) ◽  
pp. 127-132
Author(s):  
Ahmed Eltwati ◽  
Alaa A. A. Elkaseh

In recent decades, escalating traffic volumes initiate asphalt pavements revealed to larger stresses, which can create premature distresses. To enhance the resistance to distresses, modification of the asphalt mixtures has been studied extensively. The objective of this paper is to evaluate the performance of asphalt pavement made with various bitumen types and also different thicknesses. The bitumen types used were conventional asphalt (Ac 60-70) and polymer modified asphalt (PG 76-22). The thickness of asphalt samples tested was 70, 80, and 90 mm. In this study, Accelerated Pavement Testing (APT) was conducted to evaluate the rut depth in the surface of the pavement. The experiment was run up to 20,000 cycles. The results revealed polymer has a significant effect on pavement resistance to rutting. The resistance can be increased by up to 30%. In addition, the rutting occurred rapidly for the first 3,000 cycles. Beyond 3,000, the deformation is increased slowly.  On the other side, the results showed that as the HMA thickness increases as the resistance to deformation increases. We, therefore, can conclude that adding particles of polymer to HMA could improve the structural performance of pavement i.e. rutting resistance and reduce the thickness of the surface


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