Asphalt mixture

At levels below 15 volume percent (26 weight percent) properties are similar to conventional asphalt mixtures. 

Saylak, D., et. al., "Sulphur-Asphalt Mixtures Using Poorly Graded Sands", Transportation Engineering Journal, ASCE, Volume 101, No. 1, Proc. Paper 11106, February, 1975, pp. 97-113. 

Gallaway, . M., and Saylak, D., "Sulphur Extended Asphalt (SEA) - Sulphur/Asphalt Mixture Design and Construction Details - Lufkin Field Trials", FHWA Report No. FHWA-TS-... 

A traprock (diabase) aggregate used in Northern Virginia for road construction and having a past history of satisfactory service in asphaltic mixtures was chosen for study. 

These data are derived from the Marshall design curves (10) the "optimum" contents meet all the criteria established for asphaltic mixtures. The optimum Sulphlex-233 content is at a slightly higher than equal volume replacement of the optimum AC-20 content. Reference (10) presents a fuller discussion of this topic. 

No precise correlation is available between the immersion-compression test and results to be expected from pavements in the field. The test provides comparative guidance on water damage susceptibility. For the diabase aggregate, the Sulphlex-233 mixtures measured dry, and after immersign in the case of wet specimens, exceed the 300 psi (2.07 x 10 pascal) minimum compressive strength usually considered necessary for acceptable mixture performance in the field. Retained strengths generally fall below the 70 percent criterion considered acceptable for asphaltic mixtures. 

The current sulfur-asphalt technologies are the result of research and development carried out since the late 1960 s, but the sulfur-asphalt concept is far from new. The foundation was laid in the 1930 s by Bencowitz 9) and his co-workers who produced and patented sulfur-asphalt mixtures which had several advantages over regular asphalt. 

Once mixed, the material can be handled using any equipment suitable for asphalt mixtures. As consistency can be varied from the equivalent of zero slump concrete to that of a sloppy mortar, the molten mix can be used for precast, slip-formed, extended or poured-in-place applications. 

Akili, W., "Preliminary Investigation of Sulphur-Asphalt Mixtures Using Local Materials", Research Inst., Univ. Pet.and Min., Saudi Arabia, 1979. 

Ground albedo mixture of concrete, asphalt. mixture of rocks, vegetation,... 

Research on the use of crumb rubber in asphalt paving needs to be intensified and brought to a conclusion. Research on newer forms of rubber and asphalt mixtures, some without patent protection (thus available at lower cost), needs to be continued. Research on how asphalt-rubber and rubber modified asphalt concrete can best be recycled should be performed. 

Takallou, H.B., RG. Hicks, and S.C. Esch. Effect of Mix Ingredients on the Behavior of Rubber-Modified Asphalt Mixtures. State of Alaska, Department of Transportation. November 1985. 

When it is necessary to collect the gases liberated during the electrochemical process because they are either the product required or a troublesome byproduct, the vessel is closed by a suitable cover which usually is used to support the electrodes. In the case of the filter-press electrolyzers with bipolar electrodes the top of the frames usually serves as a cover. Eleotrolyzers with monopolar electrodes are closed by covers made of steel, concrete, cement, stoneware, etc. Seals between covers and vessels or electrodes are made of asbestos cord, bitumen, asphalt, mixture of kaolin and tar, cement, synthetic resins, etc. 

Figure 11. Modification of temperature susceptibility of asphalt mixtures with sulfur...

Sulphur/Asphalt Mixture Design and Construction Details—Lufkin Field... 

Both Ki and K2 are fatigue parameters which vary with the composition of the asphalt mixture. Figures 2 and 3 present the variation of Ki... 

Figure 5 shows linear regression analysis of the ITFT result. As it can be seen obviously, regressions determine fatigue fanction for the asphalt mixtures. In figure 9 is shown that reinforced specimen s slope is more than nomeinforced specimens. Away from waste rubber reduction strain in reinforced specimens regression equation for reinforced specimen is... 

Two important parameters can be considered and discussed, when polyamide 66 as reinforcing fibers is used in lime stabilized clayey sand samples namely compressive and tensile strength. In essence, in soil stabilization one of the most important factors that should be considered is the modification of tensile strength. Because, as a general rule, soils like other construction materials such as concrete and asphalt mixtures has low tensile strength. 

Six samples of waste plastics were prepared for the tests. Four of them were obtained from a size reduction facility for industrial plastics recycling. The size of the plastics particles was about 2 to 10mm. The other two were obtained by being separated from domestic wastes collected in two cities and crushed to produce the size of 2 to 5 mm particles. These plastics particles were added to an asphalt mixture in quantities from 5 to 10 percent of the aggregate volume. 

Marshall properties, dynamic stability, bending strength and strain at failure of the asphalt mixtures with each of the plastics aggregates were compared with those of a conventional asphalt mixture. Results showed that dynamic stability of asphalt mixture with a plastics aggregate which softened at the mixing temperature was higher than the conventional mixture. 

Field tests were also carried out to evaluate the constructability and performance of asphalt mixtures with plastics aggregates. 

Keyword paving material, asphalt mixture, waste plastics, recycling, Marshall test, wheel tracking test, dynamic stability, bending test. 

Waste plastics will be utilized in an asphalt mixture in two ways as follows. 

The latter may spend comparatively much waste plastics become, because they are utilized as aggregate. If the waste plastics used as aggregate have a good influence upon the properties of asphalt mixture, the latter is an effective way for plastics waste reduction. 

The particles of crushed plastics will present one of the following three states in a hot asphalt mixture, where asphalt, filler and aggregate are mixed at 150 to 170°C. 

Plastics of the first sort are soluble in the asphalt at hot-mixing and have the effect of raising the viscosity of the asphalt. But. too high viscosity of the asphalt binder may produce bad effects on the workability at construction and the flexibility of the asphalt mixture in pavement. 

Plastics of the second sort are insoluble in the asphalt and have little effect on the properties of the asphalt, but they may have some effects on the mechanical properties of the asphalt mixture. The particles of the plastics become soft and plastic at hot-mixing for making the asphalt mixture and deform at compaction, in between the aggregate particles. They become back to hard and elastic upon cooling. The elastic particles in between the aggregate particles will restrict the movement of the aggregate particles, and consequently the resistance to permanent deformation of the asphalt mixture will become higher. 

As plastics of the third sort are like aggregate particles, the addition of them will have little influence on the mechanical properties of the asphalt mixture, if the percentage of the addition is not too high. When the particles of plastics are too much or large-sized, the strength of the asphalt mixture will drop, because the particles of plastics are softer than the particles of the aggregates at even low temperature. 

The effect of the second sort plastics is worth notice. It is expected that the effect will avail the improvement of asphalt mixtures and the utilization of plastics wastes. 

Making of asphalt mixtures with the waste plastics... 

The type of asphalt mixture used in this study was a densegraded asphalt mixture, which is one of typical asphalt mixtures in Japan, and the maximum particle size of the aggregates was 13 mm. The asphalt mixture is composed of asphalt binder, filler and aggregates. 

The design asphlt contents of the asphalt mixtures with the waste plastics were determined by the procedure in the Manual for Asphalt Pavement by Japan Road Association where is applied to the conventional asphalt mixtures. 

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