Construction-Related Temperature Differentials in Asphalt Concrete Pavement: Identification and Assessment

Author(s):  
Joe P. Mahoney ◽  
Stephen T. Muench ◽  
Linda M. Pierce ◽  
Steven A. Read ◽  
Herb Jakob ◽  
...  

Numerous Washington State Department of Transportation (WSDOT) paving projects have experienced a cyclic occurrence of premature failure of open-textured asphalt concrete (AC) pavement sections by fatigue cracking, raveling, or both, generally called “cyclic segregation” or “endof-load segregation.” This resulted in an initial study in which mat temperature differentials were observed during laydown. In turn, this led to the current study and the reported results. Pavement temperature differentials result from placement of a cooler portion of the hot-mix mass into the mat. This cooler mass generally constitutes the crust, which can develop during hot-mix transport from the mixing plant to the job site. Placement of this cooler hot mix can create pavement areas near cessation temperature that tend to resist proper compaction (they may also exhibit tearing or roughness or appear to be open textured). These areas were observed to have decreased densities and a higher percentage of air voids (higher air voids). Four 1998 WSDOT paving projects were examined to determine the existence and extent of mat temperature differentials and associated material characteristics. An infrared camera was used to identify cooler portions of the mat, which were then sampled along with normal-temperature pavement sections. Gradation and asphalt content analysis showed no significant aggregate segregation within the cooler areas. However, these cooler portions of the mat consistently showed higher air voids than the surrounding pavement. On the basis of numerous studies that have related AC deterioration and high air voids in a mix, it is known that the areas of a mat with higher air voids may experience premature failure compared with the time to failure of the mat as a whole.

2015 ◽  
Vol 4 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Ahmed F. Al-Tameemi ◽  
Yu Wang ◽  
Amjad Albayati

Abstract Flexible or asphalt concrete pavement is the paving system most widely adopted all over the world. It has been recognized that there are many different types of the factors affecting the performance and durability of asphalt concrete pavement, including the service conditions, such as: the variation of temperature from mild to extremes and the repeated excessive axle loading as well as the inadequate quality of the raw materials. All of these when combined together are going to accelerate the occurrence of distresses in flexible pavement such as permanent deformation and fatigue cracking. As the result, there has an urgent need to enhance the ability of asphalt concrete mixture to resist distresses happened in pavement. Use of additives is one of the techniques adopted to improve pavement properties. It has been found that hydrated lime might be one of the effective additives because it is widely available and relatively cheap compared to other modifiers like polymers. This paper presents an experimental study of the hydrated-lime modified asphalt concrete mixtures. Five different percentages of the hydrated lime additive were investigated, namely (1, 1.5, 2, 2.5 and 3 percent). The hydrated lime additive was used as partial replacement of limestone filler by total weight of the aggregate. The designed Hot Mix Asphalt (HMA) concretes are for the application of three pavement courses, i.e. Surface, Leveling and Base. These mixtures are designed and tested following Marshall procedure and uniaxial repeated loading to evaluate permanent deformation at different temperatures of 20°C, 40°C and 60°C. The experimental results show that the addition of hydrated lime as a partial replacement of ordinary limestone mineral filler results a significant improvement on mechanical properties and the resistant to permanent deformation of the designed asphalt concrete mixtures.


2013 ◽  
Vol 405-408 ◽  
pp. 1782-1785
Author(s):  
Zi Ye He ◽  
Fu Xue Liu

Fatigue crack is one of the main road damage forms of asphalt pavement structure, and serious impact the asphalt pavement performance and service life. Asphalt mixture has typical viscoelastic,and can get Burgers model and viscoelastic parameters form creep test. Using finite element method of fracture mechanics, simulation under dynamic loading, research crack extending behavior of common asphalt concrete pavement and mixed with 0.2% of sisal fiber asphalt concrete pavement. From the results, it can find out that when mixed with sisal fiber, the anti-fatigue cracking performance is obvious enhancement.


2020 ◽  
Vol 6 (1) ◽  
pp. 10-28
Author(s):  
Nabil AlKofahi ◽  
Taisir Khedaywi

The stripping of asphalt cement still the most significant reason that causes the deterioration of asphalt concrete pavement. This study aims to compare and develop a systematic method for the results of stripping tests: Texas boiling, resilient modulus, and fatigue. Three types of aggregates and two types of anti-stripping additives were used. Texas boiling test, and then Marshall specimens with (6-8%) air voids subjected to medium or high moisture conditioning were used. The stripping potential evaluated by suggesting sequence tests steps for asphalt coating retained (60-80%) visually and by the resilient modulus (MR). The visual assessment of the boiling test and the rolling test is not enough to predict stripping. The degree of saturation had a very significant effect on the resilient modulus values. The use of the resilient modulus test for Marshall specimens is a reliable test to predict stripping. For the results of less than the range; add additives and re-evaluate the stripping. For results above the range; run a fatigue test with high saturation. In general, it found that the dosage of lime needed is between 1.5 to 2.0% by weight of aggregate, where for polyamine, it was between 0.75 to 1% by weight of asphalt binder. Lime additive showed better effects on stripping potential than polyamine (liquid) additive. The proposed methodology which organized by a flow chart is a sound step-by-step and practical procedure for predicting the stripping. It could be used as a guideline to assess the water susceptibility for any aggregate type


Author(s):  
Sheng Hu ◽  
Fujie Zhou ◽  
Tom Scullion

Traffic loading is one of the key factors that may cause asphalt concrete pavement fatigue cracking. Axle load spectra input provides an opportunity for evaluating the pavement response under real traffic loads throughout the pavement design life. This paper describes the methodology of incorporating axle load spectra into the mechanistic–empirical fatigue cracking model that uses a fracture mechanics method to determine crack propagation. The paper also presents the incorporation of the method into the Texas mechanistic–empirical flexible pavement design system. Several load spectra cases were studied, and the percentages of the corresponding fatigue cracking areas were predicted and compared. The comparison results confirmed the necessity of load spectra analysis. Overall, the implemented load spectra–incorporated asphalt concrete fatigue cracking model generated rational results. Further research is continuing on field validation and calibration.


1997 ◽  
Vol 1594 (1) ◽  
pp. 163-171 ◽  
Author(s):  
John A. Van Lund ◽  
Mark R. Kaczinski ◽  
Robert J. Dexter

The Lacey V. Murrow Bridge (LVM Bridge) is a 2013-m-long floating bridge on Interstate 90 across Lake Washington in Seattle, Washington. Single-support-bar, swivel-joist modular bridge expansion joint systems are located at each end of the bridge between the shore approach spans and the floating pontoons. These joints were designed for 960 mm of longitudinal movement as well as horizontal and vertical rotations caused by wind, wave, temperature, and changes in lake level elevation. A similar joint in an adjacent floating bridge had experienced premature fatigue cracking at welded attachment details because of low fatigue strength. For the LVM Bridge the joint components were fatigue tested and designed by using fatigue limit-states loads, resulting in welded attachment details with improved fatigue strength. In addition, a stiffer center beam and reduced center-beam span lengths produced lower fatigue stress ranges. Joint movements and rotations, fatigue design methodology, results of dynamic analyses, field measurements of the dynamic response, and construction details are described. The total cost of the LVM joints was 1 percent of the final bridge cost. The Washington State Department of Transportation required a 5-year guarantee for the LVM joints. These are the largest modular bridge expansion joints in the United States to be tested and designed for fatigue.


2019 ◽  
pp. 78-92
Author(s):  
Vladimir Zelenovsky ◽  
◽  
Ivan Kopinets ◽  
Arthur Onishchenko ◽  
◽  
...  

Author(s):  
Randy B. Machemehl ◽  
Feng Wang ◽  
Jorge A. Prozzi

Truck tire inflation pressure plays an important role in the tire–pavement interaction process. As a conventional approximation method in many pavement studies, tire–pavement contact stress is frequently assumed to be uniformly distributed over a circular contact area and to be simply equal to the tire pressure. However, recent studies have demonstrated that the tire–pavement contact stress is far from uniformly distributed. Measured tire–pavement contact stress data were input into an elastic multilayer pavement analysis program to compute pavement immediate responses. Two asphalt concrete pavement structures, a thick pavement and a thin pavement, were investigated. Major pavement responses at locations in the pavement structures were computed with the measured tire–pavement contact stress data and were compared with the conventional method. The computation results showed that the conventional method tends to underestimate pavement responses at low tire pressures and to overestimate pavement responses at high tire pressures. A two-way analysis of variance model was used to compare the pavement responses to identify the effects of truck tire pressure on immediate pavement responses. Statistical analysis found that tire pressure was significantly related to tensile strains at the bottom of the asphalt concrete layer and stresses near the pavement surface for both the thick and thin pavement structures. However, tire pressure effects on vertical strain at the top of the subgrade were minor, especially in the thick pavement.


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