Strategic Highway Research Program gyratory compaction for predicting air voids of Saskatchewan SPS-9A asphalt mixes after 10 years of performance in the field

2012 ◽  
Vol 39 (8) ◽  
pp. 897-905 ◽  
Author(s):  
Aziz Salifu ◽  
Curtis Berthelot ◽  
Ania Anthony ◽  
Brent Marjerison

Many Saskatchewan provincial highways exhibit permanent deformation that is mostly attributed to reduction in air voids in hot mix asphalt concrete surfacing. The Saskatchewan Ministry of Highways and Infrastructure (MHI) currently use the Marshall compaction method for hot mix asphalt concrete (HMAC) design and placement quality control and quality assurance. It has been found that the Marshall compaction method does not accurately predict field air voids. Therefore, MHI identified the need to evaluate the SuperpaveTM gyratory compaction method to predict field air voids of typical Saskatchewan asphalt mixes. This paper presents a summary of laboratory and field volumetric as well as rapid triaxial mechanistic material properties of typical Saskatchewan asphalt mixes. This research considered seven asphalt mixes from the Radisson Specific Pavement Study (SPS)-9A test site comprising two conventional Saskatchewan Marshall Type 71 mixes, five SuperpaveTM mixes, and a SuperpaveTM recycled mix. This research determined that Marshall compaction and the gyratory compaction at 1.25° gyration angle underestimate the collapse of field air voids. This research also showed that the gyratory compaction method at 2.00° angle of gyration more accurately predicted field air voids of the asphalt mixes constructed as part of test site.

2020 ◽  
Vol 40 (2) ◽  
pp. 24-33
Author(s):  
Olumide Moses Ogundipe ◽  
Emeka Segun Nnochiri

The study investigates the use of waste glass as filler in asphalt concrete. Waste glass constitutes a significant proportion of the waste generated in both developed and developing countries. Successful utilization of the waste glass in asphalt will reduce the problem faced by environmental agencies at ensuring safe disposal of the non-biodegradable waste and may improve the asphalt properties. In the study, a waste glass in form of a filler was introduced into the asphalt mix at 8%, 10%, 12%, 14%, 16%, 18% and 20% of the total mix. The asphalt concrete samples with and without waste glass as filler were subjected to the Marshall test to determine the stability, flow, air voids, void in mix aggregate and void filled with bitumen. The Marshall test results show that stability increases when increasing glass filler up to 18%, although the values were lower than of the asphalt concrete without waste glass. This implies improved resistance to fatigue for higher waste glass content. Also, the flow increases with increasing glass filler, which implies the resistance to permanent deformation which did not improve. Generally, the introduction of waste glass in the asphalt concrete is environmentally friendly, and it will aid the sustainable management of waste glass.


Author(s):  
E. R. Brown ◽  
D. I. Hanson ◽  
Rajib B. Mallick

To achieve 4.0 percent air voids in laboratory-compacted hot-mix asphalt with the Superpave gyratory compactor, different gyration levels are currently specified in the Superpave manual, each applicable to a particular combination of traffic and maximum pavement temperature. Two 1-year-old and four 2-year-old in-place densities were compared to those obtained from Superpave compaction of laboratory-prepared specimens and from compaction of reheated plant-produced mixtures. The gyration numbers corresponding to in-place density fell below 100 for all the mixes. At similar gyration levels, density of compacted, reheated, and laboratory-prepared specimens indicated an average difference of about 1 percent. Current data show that the Ndesign, Ninitial, and Nmax gyration levels may be too high, at least for lower traffic. Evaluation of the currently specified Ndesign values will be refined when the 3-year in-place density data become available.


2010 ◽  
Vol 37 (3) ◽  
pp. 489-495
Author(s):  
Curtis Berthelot ◽  
Diana Podborochynski ◽  
Ania Anthony ◽  
Brent Marjerison

This paper provides a performance comparison of mechanistic laboratory and field rutting performance of four asphalt concrete mixes constructed in 1996 at a Strategic Highway Research Program SPS-9A test site located in Saskatchewan. The asphalt mixes included two Saskatchewan Type 70 Marshall mixes and two coarse graded Superpave™ mixes and employed 150–200A and 200–300A penetration grade asphalt cement binders. The triaxial frequency sweep characterization determined that the Superpave™ mix yielded improved mechanistic structural constitutive properties when compared to the Saskatchewan Type 70 mix. In addition, improved mechanistic structural properties were observed with the mixes employing 150–200A (PG 58-28) asphalt binder relative to the 200–300A (PG 52-34) asphalt binder, particularly the Saskatchewan Type 70 mix. The 10-year rutting performance of the Radisson SPS-9A test site was evaluated and the field rutting results concurred with the triaxial frequency sweep test results. The triaxial frequency sweep characterization employed in this study appears to adequately rank asphalt mixes with respect to field rutting performance.


2017 ◽  
Vol 156 ◽  
pp. 424-434 ◽  
Author(s):  
Rodrigo Pires Leandro ◽  
Kamilla L. Vasconcelos ◽  
Liedi Légi Bariani Bernucci

Author(s):  
Ronald Collins ◽  
Haroon Shami ◽  
James S. Lai

The Georgia loaded wheel tester (LWT) developed by the Georgia Department of Transportation has been used since 1985 in the laboratory during the design stage to evaluate rutting susceptibility of asphalt concrete mixtures. In the LWT testing, asphaltic concrete is subjected to an elevated temperature in a loaded wheel system under repetitive loading conditions, and the permanent deformation induced under the wheelpath is measured. This approach to assess rutting susceptibility was thought to be much more representative than the current test methods and can provide a fast and more accurate means of assessing rutting susceptibility of asphalt concrete under actual field conditions. The asphaltic beam samples used for the LWT testing are prepared by a rolling compaction machine. The new LWT developed in 1992 is described. To promote the concept of using Georgia LWT as a supplement to the Superpave Level 1 design procedure for evaluating permanent deformation of hot-mix asphalt (HMA), a test method utilizing Superpave gyratory compactor-prepared samples to evaluate the rutting resistance of HMA by the LWT was developed. The gyratory samples placed in a specially designed mold can be tested in the LWT identical to that for performing the LWT testing on the beam samples. A test program was conducted to evaluate the applicability of the testing procedure and to develop correlations between the rut depth of asphalt mixes using the beam samples and the gyratory samples. The test program used three asphalt mixes of different degrees of rutting resistance ranging from high to low rut susceptibility. Both types of samples were tested at 40°C, 50°C, and 60°C temperatures for 8,000 cycles under the standard LWT testing procedure. The rut depth results from the beam samples and the gyratory samples showed good correlations for all three mixes tested. The test results also showed a strong relationship between the rut depth values and the air void content in the mixes.


Author(s):  
Mansour Solaimanian ◽  
Maghsoud Tahmoressi

A research project was undertaken to evaluate the production and construction variability of hot-mix asphalt concrete (HMAC) containing large quantities of recycled asphalt pavement (RAP) material. Four construction projects were selected. Two of the projects used 35 percent RAP material, while the other two used 40 and 50 percent RAP, respectively. The projects differed in size with total hot-mix ranging from 12,000 to 30,000 tons. In all cases, dedicated RAP stockpiles were used. A series of tests were performed at both the hot-mix plant laboratory and the University of Texas (UT) asphalt laboratory. The tests at the plant included extraction, gradation, and asphalt content using nuclear gauge. A number of specimens were also compacted and shipped to the Texas Department of Transportation Materials and Tests Division for Hveem stability testing. Asphalt recovery, penetration, and viscosity tests for both HMAC and RAP were conducted at the UT laboratory. Each day, four sublots were sampled. The results obtained from the tests were analyzed. The gradation and asphalt content deviations, air voids, penetrations and viscosities, and stabilities were included in the analysis. Pay adjustment factors were determined for gradation and asphalt content deviation, as well as for air voids. In general, these high-percentage RAP projects indicated higher variability than a typical HMAC project without RAP. The gradations of plant-produced mixtures were finer than the job mix formula target gradations, possibly because of aggregate crushing during the milling operation.


2007 ◽  
Vol 13 (1) ◽  
pp. 56-60 ◽  
Author(s):  
Hassan Ziari ◽  
Mahmud Ameri ◽  
Mohammad Mahdi Khabiri

Bituminous mixes are becoming increasingly important in the road industry. The road engineers identify rutting as a major source of distress in Hot Mix Asphalt (HMA) pavements. The Asphalt Mix Design Marshal method adequately addresses the aggregate and asphalt binder properties that contribute to permanent deformation. However, there is no laboratory test currently at hand to quickly predict permanent deformation susceptibility of HMA. The main purpose of this paper is to provide practical information of laboratory samples for practitioners and mix designers. Thus, relevant test procedures and results of tests conducted are reported in this paper. Two resilient behaviours of cracked sealed asphalt concrete were studied by varying temperature and time of loading to understand the crack sealed pavement behaviour under Iran conditions.


Author(s):  
Kevin D. Hall ◽  
Satish K. Dandu ◽  
Gary V. Gowda

Gyratory compaction is the centerpiece of the Strategic Highway Research Program asphalt mixture design procedure Superpave. A number of factors could potentially affect the behavior of asphalt mixes in the gyratory compactor. One of these is specimen size. Four specimen sizes each of one unmodified and two rubber-modified hot-mix asphalt concrete mixes were compacted in the Superpave gyratory compactor to determine the effect of specimen size on compaction and volumetric properties of the mixes. All specimens were compacted using a 150-mm-diameter mold. Specimens of each of the mix types were prepared using three gradations and three binder contents. Densification curves and plotting number of gyrations versus percent of theoretical maximum density were developed for each mix type/gradation/binder content combination. A strong trend in the densification data was observed, in which curves representing specimen sizes of 3500, 5000, and 6500 g were grouped together, apart from the curve representing a 2000-g specimen size. This trend, the grouping of larger specimen data apart from small specimen data, was also observed in volumetric data (optimum asphalt content, voids in mineral aggregate, and voids filled with asphalt). These trends were observed in most of the mix type/ gradation/binder content combinations. The data presented suggest that for specimens of sufficient size, for example, greater than 3500 g, specimen size does not significantly affect the volumetric or compaction properties of hot mix specimens, which supports the ruggedness of the gyratory compaction procedure.


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.


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