Balanced Mix Design Benchmarking of Field-Produced Asphalt Mixtures in Maine, U.S.

Author(s):  
Ram Kumar Veeraragavan ◽  
Derek Nener-Plante ◽  
Leslie Myers ◽  
Casey Nash ◽  
Nam H. Tran

Performance testing has been recognized by state highway agencies (SHAs) in the U.S. and the asphalt paving industry as an important tool to complement volumetric properties for improving asphalt pavement performance. Thus, Maine Department of Transportation (MaineDOT) initiated a research effort in 2019 to evaluate the cracking and rutting resistance of asphalt mixtures using several performance tests, including the Hamburg wheel-tracking test (HWTT), indirect tensile cracking test (IDEAL-CT), cyclic fatigue test, and stress sweep rutting (SSR) test. These tests were conducted on reheated common plant-produced asphalt mixtures, and results were analyzed to: (1) develop baseline rutting and cracking performance; (2) evaluate the effects of mixture properties on the performance test results; and (3) verify the performance enhancement from the extended use of polymer-modified asphalt binders. Several mixture properties, such as nominal maximum aggregate size (NMAS), binder performance grade (PG), binder content (Pb), and reclaimed asphalt pavement (RAP) %, were found to have statistically significant effects on the mixture rutting and cracking resistance, especially the HWTT and IDEAL-CT results. Based on the proposed criteria for rutting strain index (RSI) and apparent damage capacity (Sapp), the asphalt mixtures tested would provide satisfactory rutting performance under heavy traffic, and satisfactory cracking performance under standard traffic. In addition, based on the IDEAL-CT benchmarking results, mixtures with polymer-modified binder and/or smaller NMAS were found to have higher cracking tolerance index (CTindex) results. The information from the research effort will help MaineDOT to achieve its goal to move beyond sole use of volumetric properties for asphalt mixture design and acceptance with the implementation of balanced mix design (BMD) for improving the field performance of asphalt pavements.

Author(s):  
H. Barry Takallou ◽  
Hussain U. Bahia ◽  
Dario Perdomo ◽  
Robert Schwartz

The effect of different mixing times and mixing temperatures on the performance of asphalt-rubber binder was evaluated. Four different types of asphalt-rubber binders and neat asphalt were characterized using the Strategic Highway Research Program (SHRP) binder method tests. Subsequently, mix designs were carried out using both the SHRP Levels I and II mix design procedures, as well as the traditional Marshall mix design scheme. Additionally, performance testing was carried out on the mixtures using the Superpave repetitive simple shear test at constant height (RSST-CH) to evaluate the resistance to permanent deformation (rutting) of the rubberized asphalt mixtures. Also, six rectangular beams were subjected to repeated bending in the fatigue tester at different microstrain levels to establish rubberized asphalt mixtures’ resistance to fatigue cracking under repeated loadings. The results indicate that the Superpave mix design produced asphalt-rubber contents that are significantly higher than values used successfully in the field. Marshall-used gyratory compaction could not produce the same densification trends. Superpave mixture analysis testing (Level II) was used successfully for rubberized asphalt mixtures. Results clearly indicated that the mixture selected exhibited acceptable rutting and fatigue behavior for typical new construction and for overlay design. Few problems were encountered in running the Superpave models. The results of the RSST-CH indicate that rubber-modified asphalt concrete meets the criteria for a maximum rut depth of 0.5 in.; and more consistent results were measured for fatigue performance analysis using the repeated four-point bending beam testing (Superpave optional torture testing). The cycles to failure were approximately 26,000 at 600 microstrain.


Author(s):  
Jo Sias Daniel ◽  
Aaron Lachance

This research examines how the addition of recycled asphalt pavement (RAP) changes the volumetric and mechanistic properties of asphalt mixtures. A Superpave® 19-mm mixture containing 0% RAP was the control for evaluating properties of mixes containing 15%, 25%, and 40% RAP. Two types of RAP were evaluated: a processed RAP and an unprocessed RAP (grindings). Testing included dynamic modulus in tension and compression, creep compliance in compression, and creep flow in compression. Dynamic modulus and creep compliance master curves were constructed with the use of the time–temperature superposition principle to describe the behavior of each mix over a range of temperatures. The voids in mineral aggregate (VMA) and voids filled with asphalt (VFA) of the RAP mixtures increased at the 25% and 40% levels, and there was also an influence of preheating time on the volumetric properties. The dynamic modulus of the processed RAP mixtures increased from the control to 15% RAP level, but the 25% and 40% RAP mixtures had dynamic modulus curves similar to that of the control mixture in both tension and compression. The creep compliance curves showed similar trends. A combination of gradation, asphalt content, and volumetric properties is likely the cause of these trends.


Author(s):  
John A. Hinrichsen ◽  
John Heggen

The use of voids in mineral aggregate (VMA) criteria for proper mix design of hot-mix asphalt is a time-honored and fairly successful tool. Recent developments in the field of asphalt mix design have encouraged the use of mixtures with a coarse aggregate structure to resist the effect of heavy traffic loads. By using the equations presented, which account for both aggregate gradation and the volumetric properties of the materials, the mix designer is able to judge the proper VMA requirement for each unique blend of materials. By applying the new equations, the most economical mix may be selected without great risk of reduced durability. Supporting data from field application are presented to illustrate the use of the equations.


2015 ◽  
Vol 752-753 ◽  
pp. 194-198 ◽  
Author(s):  
E. Shaffie ◽  
J. Ahmad ◽  
D. Kamarun

Rutting is a common pavement failure in road pavement. Rutting occurs mainly due to several factors including increasing of vehicles numbers, environmental conditions and also due to construction and design errors. As a consequence the service life of asphalt pavement is affected and will be decreased. Various researches reported that using different types of polymers in bitumen modification could be a solution to delay deterioration of asphalt pavement. The main purpose of the study was to investigate the effect of the NPA polymer modifier on the rutting behaviour of the asphalt mixtures through Superpave designed mixtures. . Two different types of dense graded Superpave HMA mix were developed consists of Control mix and nanopolyacrylate (NPA) mix. Results showed that all the mixes passed the Superpave volumetric properties criteria which indicate that these mixtures were good with respect to durability and flexibility. Furthermore there is a significant difference between Control mix and NPA mix in terms of rutting in which rut depth after 8000 passes for Control mix was 5.94 mm while for NPA mix was 2.98 mm. The results of this investigation indicated that the Rutting test result of NPA demonstrates 3% better resistance to rutting than those prepared using Control mix. This is due to the addition of NPA to the bitumen has certainly improved the bitumen properties significantly and hence increase the resistant to rutting of the asphalt mixture. Therefore, it can be concluded that NPA polymer is feasible to be used as asphalt modifier and has potential for improvement in the field of pavement material and construction in future.


Author(s):  
Tianhao Yan ◽  
Mihai Marasteanu ◽  
Chelsea Bennett ◽  
John Garrity

In a current research effort, University of Minnesota and Minnesota Department of Transportation have been working on designing asphalt mixtures that can be constructed at 5% air voids, similar to the Superpave 5 mix design. High field density of asphalt mixtures is desired because it increases the durability and extends the service life of asphalt pavements. The paper investigates the current situation of field densities in Minnesota, to better understand how much improvement is needed from the current field density level to the desired level, and to identify possible changes to the current mix design to improve field compactability. Field densities and material properties of 15 recently constructed projects in Minnesota are investigated. First, a statistical analysis is performed to study the probability distribution of field densities. Then, a two-way analysis of variance is conducted to check if the nominal maximum aggregate size and traffic levels have any significant effect on field densities. A correlation analysis is then conducted to identify significant correlations between the compactability of mixtures and their material properties. The results show that the field density data approximately obey normal distribution, with an average field density of 93.4% of theoretical maximum specific gravity; there are significant differences in field density between mixtures with different traffic levels; compactability of mixtures is significantly correlated with fine aggregate angularity and fine aggregate gradation of the mixtures.


2021 ◽  
Vol 13 (7) ◽  
pp. 4002
Author(s):  
Seungbub Song ◽  
Chunho Yeom

This study aims to maximize the effects of reducing plastic deformation in heavy traffic intersections in urban areas by improving the aggregates and binders of asphalt mixtures in order to verify the strength effect of SMA (Stone Mastic Asphalt) mixtures compared with that of fluid-resistant asphalt mixtures. The authors examine the pavement performance and conduct an economic analysis for sustainable urban infrastructure. Additionally, to reduce plastic deformation, the study analyzed an improvement plan through experimental research based on the existing literature. First, we determined the mixing design specifications of the general asphalt fluid-resistant mixture and SMA mixture, which is known to reduce plastic deformation. Next, we confirmed the appropriateness of the raw materials and mixing design results. Finally, a performance test was conducted on plastic deformation resistance. A wheel tracking test was also conducted as a performance experiment. The test body—with a fiber grid reinforcing material installed in the SMA mixture—showed high dynamic stability, which was the most effective for reducing plastic deformation.


Author(s):  
Agathon Honest Mrema ◽  
Si-Hyeon Noh ◽  
Jae-Jun Lee ◽  
Oh-Sun Kwon

Nowadays, in order to improve asphalt pavement performance, durability and reduce environmental pollution caused by asphalt binder, many researchers are studying to modify asphalt concrete (AC) and find alternative paving materials to extend service life of asphalt pavement. One of the successful materials used in a modification of AC are fibers. Different types of fibers have been reinforced in AC mixture and improvements have been observed. This research studies the performance of glass wool fiber reinforced in a dense-graded asphalt mixture. Generally, glass fibers are known to have excellent mechanical properties such as high tensile modulus, 100% elastic recovery and a very high tolerance to heat. The glass wool fibers are commonly used as a thermal insulation material. In this research to evaluate the performance of glass wool fiber in AC, laboratory tests Marshall mix design test, Indirect tensile strength (IDT), Tensile strength ratio (TSR) and Kim test were conducted to determine a proper mix design, tensile properties, moisture susceptibility, rutting and fatigue behaviors. Results show that addition of glass wool fibers does affect the properties of AC mixture. The use of glass wool fibers showed a positive consistence results, in which it improved the moisture susceptibility and rutting resistance of the AC. Also result showed addition of fiber increased tensile strength and toughness which indicates that fibers have a potential to resist distresses that occur on a surface of the road as a result of heavy traffic loading. The overall results showed that addition of glass wool fiber in AC mixture is beneficial in improving properties of AC pavements.


Author(s):  
Mirkat Oshone ◽  
Debaroti Ghosh ◽  
Eshan V. Dave ◽  
Jo Sias Daniel ◽  
Joseph M. Voels ◽  
...  

To address asphalt pavement thermal cracking, researchers have developed performance-based evaluation tools for asphalt mixtures. A minimum fracture energy obtained from a disc-shaped compact tension test and Black space parameters determined by the stiffness and relaxation properties of asphalt mixtures are two such methods to ensure good thermal cracking resistance. Mix specifiers and producers strive to meet the requirements set by these performance-based criteria by adjusting their mix designs. However, there is a lack of information and consensus on the effect of mix design variables (such as binder grade and mix volumetrics) on thermal cracking performance of mixtures as it relates to fracture energy and Black space location. This study strives to fill this gap by quantifying the effect of: (1) recycled asphalt content, (2) effective binder content, (3) air voids, (4) asphalt film thickness, (5) voids in mineral aggregates, and (6) PG low and high temperature grades on thermal cracking resistance. A large dataset, 90 mixtures from the Minnesota Department of Transportation and 81 mixtures from University of New Hampshire database, was used for the study. The results indicate a strong correlation between binder related properties (binder content, asphalt film thickness, PG spread) and fracture energy. The correlation coefficients obtained from this study for PG spread, effective binder content, and air void can be confidently employed to achieve targeted fracture energy thresholds. The same can be achieved for the Glower-Rowe parameter at 15ºC by employing the correlation coefficients obtained for PG low temperature, virgin asphalt content, and voids in the mineral aggregate.


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