Performance-based mix design of unmodified and lime-modified hot mix asphalt

2012 ◽  
Vol 39 (7) ◽  
pp. 824-833 ◽  
Author(s):  
Sangyum Lee ◽  
Cheolmin Baek ◽  
Je-Jin Park

This paper presents the performance evaluation of unmodified and lime-modified hot mix asphalt (HMA) mixtures at varying asphalt content using asphalt mixture performance test developed from National Cooperative Highway Research Program project 9-19 and 9-29 and the viscoelastic continuum damage finite element analysis. Test methods adopted in this study are the dynamic modulus test for stiffness, the triaxial repeated load permanent deformation test for rutting, and the direct tension test for fatigue cracking. The findings from this study support conventional understanding of the effects of asphalt content and lime modification on the fatigue cracking and rutting performance. Finally, the optimum asphalt content for both lime-modified and unmodified mixtures are proposed based on the knowledge gleaned from the performance-based mix design methodology. With additional validation and calibration, the comprehensive methodology described in this paper may serve as the foundation for a performance-based HMA mix design and performance-related HMA specifications.

2019 ◽  
Vol 4 (2) ◽  
pp. 34 ◽  
Author(s):  
Md Rashadul Islam ◽  
Sylvester A. Kalevela ◽  
Shelby K. Nesselhauf

In the design of pavement infrastructure, the flow number is used to determine the suitability of a hot-mix asphalt mixture (HMA) to resist permanent deformation when used in flexible pavement. This study investigates the sensitivity of the flow numbers to the mix factors of eleven categories of HMAs used in flexible pavements. A total of 105 specimens were studied for these eleven categories of HMAs. For each category of asphalt mixture, the variations in flow number for different contractors, binder types, effective binder contents, air voids, voids in mineral aggregates, voids filled with asphalt, and asphalt contents were assessed statistically. The results show that the flow numbers for different types of HMA used in Colorado vary from 47 to 2272. The same mix may have statistically different flow numbers, regardless of the contractor. The flow number increases with increasing effective binder content, air voids, voids in mineral aggregates, voids filled with asphalt, and asphalt content in the study range of these parameters.


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):  
Ben C. Cox ◽  
Jonathan Easterling ◽  
W. Griffin Sullivan ◽  
Alex Middleton ◽  
Isaac L. Howard

In recent years, the asphalt paving industry has been strained by numerous factors including increased asphalt binder costs, funding that has not kept up with material costs, increased societal pressure to recycle, and deteriorating pavement networks. Mix design should account for the market in which it is used, which is very different now than when today’s volumetric mix design practices were developed (many of the aforementioned factors were less present). Given this reality, a statewide database of all 1,452 approved mix designs in Mississippi from 2005 to 2018 was compiled and analyzed, and the objective of this paper is to present findings, trends, and unintended consequences of exclusive reliance on volumetrics. With volumetrics-only mix design, asphalt content is primarily controlled by voids in mineral aggregate (VMA), which is influenced by aggregate bulk specific gravity (Gsb). Minor Gsb deviations (i.e., within AASHTO d2 s limits), can significantly affect VMA, so much so that 99% of Mississippi’s mixes could be failing VMA while reported VMA passes. This allows mix manipulation and economization, with 0.8% asphalt content reductions possible while still meeting volumetric requirements. Recycled materials can exacerbate this issue, and common approaches to increase asphalt content (decreasing design gyration level or using finer gradations) are ineffective with fixed VMA requirements. Overall, the mix design database analysis agrees with numerous smaller studies but does so with an entire state’s actual practice. This presents a compelling case that volumetrics-only mix design has limitations, and supports ongoing efforts to reintegrate mechanical tests.


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2084 ◽  
Author(s):  
Piotr Mackiewicz ◽  
Antoni Szydło

We present two methods used in the identification of viscoelastic parameters of asphalt mixtures used in pavements. The static creep test and the dynamic test, with a frequency of 10 Hz, were carried out based on the four-point bending beam (4BP). In the method identifying viscoelastic parameters for the Brugers’ model, we included the course of a creeping curve (for static creep) and fatigue hysteresis (for dynamic test). It was shown that these parameters depend significantly on the load time, method used, and temperature and asphalt content. A similar variation of parameters depending on temperature was found for the two tests, but different absolute values were obtained. Additionally, the share of viscous deformations in relation to total deformations is presented, on the basis of back calculations and finite element methods. We obtained a significant contribution of viscous deformations (about 93% for the static test and 25% for the dynamic test) for the temperature 25 °C. The received rheological parameters from both methods appeared to be sensitive to a change in asphalt content, which means that these methods can be used to design an optimal asphalt mixture composition—e.g., due to the permanent deformation of pavement. We also found that the parameters should be determined using the creep curve for the static analyses with persistent load, whereas in the case of the dynamic studies, the hysteresis is more appropriate. The 4BP static creep and dynamic tests are sufficient methods for determining the rheological parameters for materials designed for flexible pavements. In the 4BP dynamic test, we determined relationships between damping and viscosity coefficients, showing material variability depending on the test temperature.


Author(s):  
Stephen B. Seeds ◽  
Rudramunniyappa Basavaraju ◽  
Jon A. Epps ◽  
Richard M. Weed

The primary objective of the FHWA-sponsored WesTrack project is to further the development of performance-related specifications for hotmix asphalt construction. This objective is being achieved, in part, through the accelerated loading of a full-scale test track facility in northern Nevada. Twenty-six hot-mix asphalt test sections constructed to meet the criteria set forth in a statistically based experiment design are providing performance data that will be used to improve existing (or develop new) pavement performance prediction relationships that better account for the effects that “off-target” values of asphalt content, air-void content, and aggregate gradation have on such distress factors as fatigue cracking, permanent deformation, roughness, raveling, and tirepavement friction. The concept of the planned new performance-related specification and how it will incorporate the modified pavement performance prediction models are described. The current plan for assessing contractor pay adjustments (i.e., penalties and bonuses) based on data collected from the as-constructed pavement is also discussed.


2017 ◽  
Vol 2633 (1) ◽  
pp. 108-116 ◽  
Author(s):  
Max A. Aguirre ◽  
Marwa M. Hassan ◽  
Sharareh Shirzad ◽  
Louay N. Mohammad ◽  
Samuel B. Cooper

The use of recycled asphalt shingles (RAS) in asphalt paving construction represents a sustainable approach to reduce virgin material consumption and negative environmental effects, as well as the cost of asphalt pavement. However, many challenges are yet to be addressed about the use of RAS in paving applications. This study evaluated the effect of the incorporation of postconsumer waste shingles and rejuvenators on the performance of hot-mix asphalt. Four asphalt rejuvenators—one bio-oil and three synthetic oils—were evaluated. A set of laboratory tests was conducted to characterize the performance of asphalt mixtures against permanent deformation and fatigue cracking. The addition of 5% RAS showed an improvement in permanent deformation when compared with a conventional mixture with no RAS. Yet the addition of asphalt rejuvenator products slightly decreased the performance against permanent deformation. On the basis of Hamburg wheel-tracking device test results, the addition of RAS did not adversely affect moisture resistance. Yet semicircular bending test results showed that the asphalt mixtures that contained asphalt rejuvenators had a lower critical strain energy release rate than the minimum threshold value (0.5 kJ/m2), which indicated a greater susceptibility to intermediate-temperature cracking.


2015 ◽  
Vol 10 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Marcin Gajewski ◽  
Dariusz Sybilski ◽  
Wojciech Bańkowski

The main goal of this paper is to propose the performance parameter for binder which is good for quality prediction of asphalt mixture in frame of resistance to permanent deformation (rutting). Additionally, correlation between, proposed by the authors, repeatable shear creep-recovery test carried out on binder and bituminous mixture rutting test is under evaluation. The results are analysed and correlation between the proposed functional parameter and rut depth is shown. Thanks to that it is possible to claim that expensive rutting test procedure can be assisted with simple test carried out in dynamic shear rheometer at the initial mix design procedure.


2008 ◽  
Vol 5 (1) ◽  
pp. 53
Author(s):  
Juraidah Ahmad ◽  
Mohd Yusof Abdul Rahman ◽  
Zainab Mohamed

Aggregates and binder are the two main constituents that make up hot mix asphalt (HMA). Since a wide variety of mineral aggregate is used to produce Hot Mix Asphalt (HMA), proper evaluation of the mineral aggregate properties is important to ensure good performance of asphalt mixture. Unlike Superpave system, Marshall and Hveem method do not incorporate aggregate criteria into their procedures. The Superpave Highway Research Programme (SHRP) modified the Delphi process to include aggregate properties which are divided into two categories; consensus and source. The consensus properties include aggregate angularity, flat and elongated particles and sand equivalent to ensure aggregate quality is sufficient to provide satisfactory HMA performance for all design traffic levels. The source properties are often used to qualify local source of aggregate which include abrasion, deleterious materials and soundness test. In this study, granite aggregates were collected from northern, central and southern region of Peninsular Malaysia. Results of the aggregate testing showed that Malaysian aggregates are durable and of good quality. These aggregates conformed to the criteria as required in the Superpave system, hence suitable for use in the mix design.


2019 ◽  
Vol 5 (12) ◽  
pp. 2535-2553 ◽  
Author(s):  
Saif Al-din Majid Ismael ◽  
Mohammed Qadir Ismael

Durability of hot mix asphalt (HMA) against moisture damage is mostly related to asphalt-aggregate adhesion. The objective of this work is to find the effect of nanoclay with montmorillonite (MMT) on Marshall properties and moisture susceptibility of asphalt mixture. Two types of asphalt cement, AC(40-50) and AC(60-70) were modified with 2%, 4% and 6% of Iraqi nanoclay with montmorillonite. The Marshall properties, Tensile strength ratio(TSR) and Index of retained strength(ISR) were determined in this work. The total number of specimens was 216 and the optimum asphalt content was 4.91% and 5% for asphalt cement (40-50) and (60-70) respectively. The results showed that the modification of asphalt cement with MMT led to increase Marshall stability and the addition of 6% of MMT recorded the highest increase, where it increased by 26.35% and 22.26% foe asphalt cement(40-5) and(60-70) respectively. Also, the addition of MMT led to increase moisture resistance of asphalt mixture according to the increase in TSR and IRS. The addition of 4% and 6% of MMT recorded the highest increase in TSR and IRS for asphalt cement (40-50) and (60-70) respectively, where they increased by 11.8% and 17.5% respectively for asphalt cement (40-50) and by 10% and 18% respectively for asphalt cement (60-70).


Author(s):  
Oloan Sitohang ◽  
Silvia Sinuhaji

Mount Sinabung located in Karo regency North sumatera has continuously been erupting since 2010, generating vast amount of waste in the form of volcanic ash. This research aims to investigate the feasibility of utilizing this volcanic ash in asphalt mixture. We used volcanic ash to replace the conventional filler material from stone crush. Sinabung volcanic ash has lower specific gravity,therefore could fill more void in the asphalt mixture, which can affect the value of Marshall test criteria. Asphalt mixture in this study uses the procedure of Hot Mix Asphalt with mixing temperature ranging from 135°C - 150°C. The result shows that the use of Sinabung volcanic ash is feasible to replace the conventional stone crush filler material in these conditions: optimum asphalt content is 6.85%; percentage of volcanic ash-stone ash 50%-50%. According to national standards issued by Bina Marga of Ministry of Public works, the following values comply with the required value. Bulk density density 2.416 kg/cm3, air void 4.724%, Void in Mineral Aggregat 18.667 Void Fillet withAsphalt 74.706%, stability 1000,992 kg, Marshall quotient 3.132 kN/mm, and flow 3.133 mm.


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