Evaluation of Superpave Gyratory Compaction of Hot Mix Asphalt

1998 ◽  
Vol 1638 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Rajib B. Mallick ◽  
Shane Buchanan ◽  
E. Ray Brown ◽  
Mike Huner
Keyword(s):  
Specific Gravity ◽  
Correction Factor ◽  
Hot Mix Asphalt ◽  
Design System ◽  
Volumetric Properties ◽  
Superpave Gyratory Compactor ◽  
Gyratory Compaction ◽  
Back Calculation ◽  
Crushed Aggregate

The effect of restricted zone on volumetric properties of mixes consisting of all crushed, and all crushed and partially uncrushed, materials was evaluated. For a given aggregate blend, gradations below or above the restricted zone provided higher voids in mineral aggregate (VMA) than mixes through the restricted zone. Mixes with crushed aggregate provided higher VMA than mixes with partially crushed aggregate. It is recommended that further work be conducted to evaluate the effect of different types and shapes of aggregates on the volumetric properties of specimens compacted with the Superpave gyratory compactor. According to the current Superpave mix design system, the bulk specific gravity of a compacted specimen at any gyration is back calculated from the bulk specific gravity determined at Nmaximum and a correction factor determined at Nmaximum. This procedure assumes that the correction factor is constant at all gyrations. A part of this study was carried out to compare the correction factors obtained at different gyration levels during compaction of hot mix asphalt and to evaluate the change in correction factor with gyration levels. Specimens were compacted at different gyration levels, and the bulk specific gravity of each was determined at each gyration level. Bulk specific gravities at each of the gyration levels were also obtained by back calculation from bulk specific gravity at Nmaximum. The correction factor was found to decrease and become close to constant at higher gyration levels. At lower gyrations, densities were found to be greater than those obtained by back calculation. It is recommended that mixes be compacted to Ndesign for determination of design asphalt content.

scholarly journals SIFAT VOLUMETRIK CAMPURAN LASTON MENGGUNAKAN ASPAL MODIFIKASI GETAH PINUS DAN LIMBAH STYROFOAM

2021 ◽  
Vol 7 (1) ◽  
pp. 66-77
Author(s):  
Ratna Yuniarti ◽  
Hasyim Hasyim ◽  
Rohani Rohani ◽  
Desi Widianty
Keyword(s):  
Specific Gravity ◽  
Asphalt Concrete ◽  
Hot Mix Asphalt ◽  
Negative Impact ◽  
Volumetric Properties ◽  
Mineral Aggregate ◽  
Modified Asphalt ◽  
Pine Resin ◽  
Road Pavement

Sifat volumetrik campuran pada laston merupakan salah satu faktor yang menentukan durabilitas (keawetan) lapis perkerasan jalan. Untuk meningkatkan keawetan lapis perkerasan jalan dan mengurangi dampak negatif terhadap lingkungan dapat dilakukan antara lain melalui modifikasi aspal dengan getah pinus dan limbah styrofoam. Tulisan ini bertujuan untuk mengkaji sifat volumetrik campuran laston menggunakan aspal modifikasi getah pinus dan limbah styrofoam tersebut. Sifat volumetrik campuran laston yang dikaji adalah rongga dalam campuran, rongga di antara mineral agregat, rongga terselimuti aspal, density dan bulk specific gravity. Pada penelitian ini digunakan agregat bergradasi rapat yang dicampur dengan aspal modifikasi pada suhu 155 oC dan dipadatkan 75 kali pada kedua sisinya. Pada seluruh benda uji, prosentase limbah styrofoam yang digunakan adalah 6% sedangkan getah pinus sebesar 0%, 1%, 2% dan 3% terhadap berat aspal modifikasi.  Hasil penelitian menunjukkan bahwa campuran laston yang menggunakan aspal modifikasi getah pinus menghasilkan nilai VFB, density dan bulk specific gravity lebih besar serta nilai VIM dan VMA lebih kecil dibandingkan dengan campuran yang menggunakan aspal modifikasi limbah styrofoam. Dengan nilai VIM dan VMA lebih kecil, campuran yang menggunakan aspal modifikasi getah pinus menghasilkan daya ikat lebih kuat sehingga memiliki durabilitas lebih tinggi. Ditinjau dari persyaratan laston sebagai lapis aus pada perkerasan jalan, penggunaan getah pinus dan limbah styrofoam sebagai modifier aspal memenuhi persyaratan volumetrik campuran. Volumetric properties of asphalt concrete is important factor to determine the durability of road pavement. Improvement the durability of road pavement and reducing negative impact of the environment can be done by using modified asphalt. This article aims to know the volumetric properties of  hot mix asphalt using pine resin and waste styrofoam as asphalt modifier. The volumetric properties include voids in mix, voids in the mineral aggregate, voids filled with bitumen, density and bulk specific gravity.  In this study, a continuously graded aggregate was used and mixed with modified asphalt at 155 oC and compacted with 75 blows on both sides. The percentage of waste styrofoam was 6% whereas the percentages of pine resin where  0%, 1%, 2% and 3% by weight of modified asphalt. From the analysis, it can be concluded that asphalt concrete containing pine resin as  modifier strengthen the binding between asphalt and agregate, due to increasing value of voids filled with bitumen (VFB), density and bulk specific gravity. Durability of asphalt concrete using pine resin as modifier was higher than that of asphalt concrete using waste styrofoam because of decreasing value of voids in mix (VIM) and voids in the mineral aggregate (VMA). Based on the specification of  asphalt concrete wearing course, the use of pine resin and waste styrofoam as asphalt modifier has fulfilled volumetric properties requirements.

Evaluation of Superpave Gyratory Compaction of Hot-Mix Asphalt

1996 ◽  
Vol 1543 (1) ◽  
pp. 145-150
Author(s):  
E. R. Brown ◽  
D. I. Hanson ◽  
Rajib B. Mallick
Keyword(s):  
Hot Mix Asphalt ◽  
Current Data ◽  
Average Difference ◽  
Density Data ◽  
Air Voids ◽  
Superpave Gyratory Compactor ◽  
Gyratory Compaction ◽  
Pavement Temperature

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.

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.

Effect of Specimen Size on Compaction and Volumetric Properties in Gyratory Compacted Hot-Mix Asphalt Concrete Specimens

1996 ◽  
Vol 1545 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Kevin D. Hall ◽  
Satish K. Dandu ◽  
Gary V. Gowda
Keyword(s):  
Asphalt Concrete ◽  
Hot Mix Asphalt ◽  
Asphalt Mixture ◽  
Design Procedure ◽  
Specimen Size ◽  
Binder Content ◽  
Volumetric Properties ◽  
Strong Trend ◽  
Number Of Factors ◽  
Gyratory Compaction

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.

Determination of Specific Gravity of Live Hogs by Suppressed Zero Techniques

1967 ◽  
Vol 26 (1) ◽  
pp. 50-57
Author(s):  
V. M. Hix ◽  
A. M. Pearson ◽  
E. P. Reineke ◽  
T. A. Gillett ◽  
L. J. Glacoletto
Keyword(s):  
Specific Gravity
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