Superpave® Laboratory Compaction Versus Field Compaction

2003 ◽  
Vol 1832 (1) ◽  
pp. 201-208 ◽  
Author(s):  
Robert L. Peterson ◽  
Kamyar C. Mahboub ◽  
R. Michael Anderson ◽  
Eyad Masad ◽  
Laith Tashman
Keyword(s):  
Mechanical Properties ◽  
Design Process ◽  
Mix Design ◽  
Air Voids ◽  
Superpave Gyratory Compactor ◽  
Asphalt Mix ◽  
Field Compaction ◽  
Shear Tester

Laboratory compaction is an important part of asphalt mix design. For the mix design process to be effective, laboratory compaction must adequately simulate field compaction. In this study mechanical properties measured with the Superpave® shear tester were used to evaluate field compaction and laboratory compaction. The field compaction consisted of three test sections with different compaction patterns. The laboratory compaction used the Superpave gyratory compactor with adjustments to several parameters. Results of this study indicate that current gyratory protocol produces specimens with significantly different mechanical properties than those of field cores produced with the same material and compacted to the same air voids. Results also show that adjustments to certain parameters of the gyratory can produce specimens that better simulate the mechanical properties of pavement cores.

Evaluation of Ability of Superpave Shear Tester To Differentiate Between Mixtures with Different Aggregate Sizes

1998 ◽  
Vol 1630 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Pedro Romero ◽  
Walaa S. Mogawer
Keyword(s):  
Aggregate Size ◽  
Complete Analysis ◽  
Maximum Aggregate Size ◽  
Air Voids ◽  
Asphalt Cement ◽  
Testing Sequence ◽  
Superpave Gyratory Compactor ◽  
Constant Height ◽  
Direct Measurements ◽  
Shear Tester

A study was conducted to determine whether the results from the Superpave shear tester (SST) could measure the effect of nominal maximum aggregate size on rutting susceptibility of asphalt mixtures without the need of a model. Four mixtures were analyzed using direct measurements from the SST. Two of the mixtures were prepared with AC-5 asphalt cement and nominal maximum aggregate sizes of 19.0 mm and 37.5 mm. The other two were prepared with AC-20 asphalt cement and the same two gradations. The results were analyzed statistically and compared with the performance of the respective mixtures tested by the FHWA Accelerated Loading Facility (ALF). The specimens were compacted to a target air voids of 7 percent using the Superpave gyratory compactor. The testing sequence consisted of performing the simple shear at constant height (SSCH) test followed by the frequency sweep at constant height (FSCH) test at 40°C and 58°C. These temperatures were chosen because they represent, respectively, the highest temperature used in Superpave complete analysis and the target pavement temperature at 20 mm depth used in the ALF tests. After the SSCH and FSCH tests, the repeated shear at constant height (RSCH) test was performed on all samples at 40°C. The ALF provided a significant decrease in rutting susceptibility with increase in aggregate size; however, the SST was unable to separate mixtures with the same binders and the two different nominal maximum aggregate sizes.

Critical Review of Voids in Mineral Aggregate Requirements in Superpave

1998 ◽  
Vol 1609 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Prithvi S. Kandhal ◽  
Kee Y. Foo ◽  
Rajib B. Mallick
Keyword(s):  
Film Thickness ◽  
Mix Design ◽  
Rational Approach ◽  
Asphalt Mixes ◽  
Mineral Aggregate ◽  
Superpave Gyratory Compactor ◽  
Asphalt Mix ◽  
Compactive Effort ◽  
Asphalt Content ◽  
Asphalt Film

Reports of increased difficulties in meeting the minimum voids in mineral aggregate (VMA) requirements have surfaced with the recent use of Superpave volumetric mix design. The low VMA of Superpave mixes generally can be contributed to the increased compactive effort by the Superpave gyratory compactor. This has led to the increased use of coarser asphalt mixes (gradations near the lower control points). However, the minimum VMA requirements in Superpave volumetric mix design for these coarse mixes are the same as those developed for the dense mixes designed by the Marshall method. Literature review has indicated that the rationale behind the minimum VMA requirement was to incorporate at least a minimum permissible asphalt content into the mix to ensure its durability. Studies have shown that asphalt mix durability is directly related to asphalt film thickness. Therefore, the minimum VMA should be based on the minimum desirable asphalt film thickness instead of on a minimum asphalt content because the latter will be different for mixes with different gradations. Mixes with coarse gradation (and, therefore, a low surface area) have difficulty meeting the minimum VMA requirement based on minimum asphalt content despite thick asphalt films. A rational approach based on a minimum asphalt film thickness has been proposed and validated. The film thickness approach represents a more direct, equitable, and appropriate method of ensuring asphalt mix durability, and it encompasses various mix gradations.

Effect of Aggregate Degradation on Specimens Compacted by Superpave Gyratory Compactor

1997 ◽  
Vol 1590 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Ronald Collins ◽  
Donald Watson ◽  
Andrew Johnson ◽  
Yiping (Peter) Wu
Keyword(s):  
Los Angeles ◽  
Volumetric Properties ◽  
Los Angeles Abrasion ◽  
Superpave Gyratory Compactor ◽  
Asphalt Mix ◽  
Field Compaction ◽  
Gyratory Compaction ◽  
Vibratory Compaction ◽  
Level I ◽  
Compaction Method

Aggregate degradation during gyratory compaction may cause changes in the original gradation of the aggregate, and it may also affect volumetric requirements for Superpave Level I mix design. The effect of aggregate degradation on the design gradation and final volumetric properties of the asphalt mix compacted by the Superpave gyratory and Astec vibratory compactors was evaluated. Because vibratory compaction is an alternative compaction method that simulates field compaction, a vibratory compactor developed by Astec Industries, Inc., was used for comparison with the Superpave gyratory compactor. Aggregates with high and low Los Angeles abrasion losses were used to evaluate the effect of aggregate toughness or abrasion resistance on gradation change and volumetric properties. The changes in the amount of material passing the 0.075-mm sieve due to aggregate degradation during compaction were not significant enough to prevent specimens from meeting dust proportion requirements, regardless of whether low-or high-abrasion loss aggregates were used. A mix containing high-abrasion aggregate was less likely to meet restricted zone requirements than a mix using low-abrasion aggregate after degradation resulting from compaction.

scholarly journals The Effect of Cow Dung Ash as A Filler on The Mechanical Characteristics of Hot Mix Asphalt

2022 ◽  
Vol 961 (1) ◽  
pp. 012041
Author(s):  
Abdulrasool Thamer Abdulrasool ◽  
Yasir N. Kadhim ◽  
Wail Asim Mohammad Hussain ◽  
Ghazi Jalal Kashesh ◽  
Hayder Adnan Abdulhussein
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Cow Dung ◽  
Replacement Rate ◽  
Asphalt Mixes ◽  
Air Voids ◽  
Traffic Loads ◽  
Asphalt Mix ◽  
Marshall Stability ◽  
Modify Asphalt

Abstract Highway pavements are being exposed to increasing traffic loads and severe environmental conditions, resulting in reduced service life. A lot of studies have been conducted to modify asphalt by using different materials, especially to replace the ordinary filler. Because the behaviour of the hot asphalt mix is influenced by the fillers. The use of unusual materials as fillers in asphalt mixes can help to improve the mix’s characteristics. As a result, this study uses cow dung ash materials with various replacement ratios as fillers to investigate the mechanical properties of asphalt. In the asphalt mix, a replacement percentage of limestone (0%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, and 100%) was utilized. After that, various tests were performed such as Marshall stability, Marshall flow, voids in mineral aggregate, theoretical maximum specific gravity, air voids. The results revealed a significant improvement in the asphalt mix’s behaviour, as well as an increase in the replacement percentage. According to the findings, the 50% replacement rate has the highest Marshall stability which is equal to 11.11 with a 33.5% rise and the lowest flow of 3 with a 17.83% decrease when compared to the reference mix. As a result, cow dung ash can be used as a filler to modify the mechanical properties of the asphalt mix.

scholarly journals Estimating Optimum Compaction Level for Dense-Graded Hot-Mix Asphalt Mixtures

2010 ◽  
Vol 7 (1) ◽  
pp. 11 ◽  
Author(s):  
Khalid Al Shamsi ◽  
Louay N. Mohammad
Keyword(s):  
Force Measurement ◽  
Asphalt Mixtures ◽  
Air Voids ◽  
Superpave Gyratory Compactor ◽  
Field Compaction ◽  
Traffic Level ◽  
Compaction Energy ◽  
High Structural Stability ◽  
Compaction Force ◽  
Using Data

 A critical step in the design of asphalt mixtures is laboratory compaction. Laboratory compaction should reflect field compaction and should produce mixtures that are economical and possess high structural stability. During the compaction process, asphalt mixtures are subjected to certain amount of compaction energy in order to achieve the required density. The Superpave volumetric mix design is based on compacting HMA mixtures to a specified compaction level described by the number of gyrations from the Superpave gyratory compactor (SGC). This level is termed Ndes and represents the required energy (based on the traffic level expected) to densify the mixture to a 4% air voids level. This paper re-examines the Superpave compaction requirements through extensive laboratory investigation of the response of a number of asphalt mixtures to the applied compaction energy. It also presents an alternative method to estimate the number of gyrations at which a mixture first reaches an optimum aggregate interlock and hence prevents overcompaction problems that might result in unstable aggregate structures or dry asphalt mixtures. A total of 12 HMA mixtures were studied. During compaction, force measurement was made using the pressure distribution analyzer (PDA). The compaction characteristics of the mixtures were analyzed using data from the PDA and the traditional Superpave Gyratory Compactor (SGC) results. 

Comparison of Superpave and Marshall Mixtures for Low-Volume Roads and Shoulders

1998 ◽  
Vol 1609 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Affan Habib ◽  
Mustaque Hossain ◽  
Rajesh Kaldate ◽  
Glenn Fager
Keyword(s):  
Mix Design ◽  
River Sand ◽  
Low Volume Roads ◽  
Superpave Gyratory Compactor ◽  
Asphalt Content ◽  
Low Volume ◽  
Project Site ◽  
Axle Loads ◽  
Crushed Limestone ◽  
Asphalt Film

Superpave and Marshall mix designs using local aggregates were done to study the suitability of the Superpave mix design as compared with the Marshall mix design for low-volume roads, especially shoulders. The project site was Kansas Route 177 in northeast Kansas. Three locally available aggregates, crushed limestone and coarse and fine river sands, were used in this study. Five blends with varying proportions of coarse and fine river sands were selected. Mix samples were compacted in the Superpave gyratory compactor with the applicable number of gyrations and were compacted with the Marshall hammer by using 50 blows per face. Bulk densities of the compacted samples and maximum specific gravities of loose samples also were measured for each blend. The results show that the Superpave mix design for low-volume roads and shoulders results in lower estimated asphalt content than does the Marshall method. The required asphalt content increases as the proportion of coarse river sand increases in the mix. Superpave requirements for the voids filled with asphalt (VFA) for low-volume traffic, that is, less than 0.3 million equivalent single-axle loads, appeared to be too high. High asphalt film thicknesses were computed for the mixtures that did not meet the Superpave VFA requirements. Lowering the design number of gyrations (Ndes) for compaction of samples would result in increased asphalt requirement for the Superpave mixture with a given gradation.

scholarly journals Effect of Adding Crushed Glass to Asphalt Mix

2016 ◽  
Vol 62 (2) ◽  
pp. 35-44 ◽  
Author(s):  
Y. Issa
Keyword(s):  
Specific Gravity ◽  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Waste Glass ◽  
Maintenance Cost ◽  
Original Sample ◽  
Air Voids ◽  
The World ◽  
Asphalt Mix

Abstract The need to modify conventional pavement rises due to high maintenance cost of the highway systems. With the continuously increased consumption, a large amount of waste glass materials is generated annually in the world. This paper aims to study the performance of pavement asphalt in which a fractional aggregate is replaced with crushed glass. In this paper, some important properties of asphalt mix, including stability, flow, specific gravity and air voids are investigated. The original sample is prepared without adding glass for different percentages of bitumen. Other samples are prepared by adding crushed glass to the mix with 5%, 10%, and 15% by aggregate weight. The results show that the properties of glass-asphalt mixture are improved in comparison with normal asphalt pavement. It is concluded that the use of waste glass in asphalt pavement is desirable.

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