01555153

Component

When an styrene-butadiene-styrene (SBS) mixture is produced in warm mix asphalt (WMA) technology, the materials should be heated to a level high enough to maintain its workability due to its highly viscous nature. The SBS-modified hot mix asphalt (HMA) (MHMA) mixtures are produced at approximately 20-30°C higher than normal (unmodified) mixtures. If a modified WMA (MWMA) mixture is produced at a lower temperature, the MWMA mixture will be weaker than the HMA due to the incomplete aggregate drying and binder coating. Therefore, using an adequately high short-term aging temperature (STAT) is important for MWMA mixtures. This study examined STATs for SBS MWMA mixtures based on two high-temperature properties (wheel tracking: WT, and deformation strength: SD), and one ambient-temperature property (indirect tensile strength: ITS), using four SBS brands. MWMA mixtures were prepared in three different WMA level STATs of 125, 135 and 145°C. Statistical analyses showed that the three properties of the mixtures produced by a STAT of 125°C were significantly lower than those of other STATs, at an α = 0.05 level. The STATs of 135°C and 145°C were acceptable for certain SBSs, but not for others. Therefore, properties of SBS MWMA mixtures were highly dependent upon STATs which significantly affect the workability and compaction. Since MHMA mixes showed significantly better properties than MWMA mixes, temperatures higher than 145°C may be required for some MWMA mixes to perform similarly to the HMA PMA mixes. However, it may still not be possible that the MWMA mix is comparable or better than MHMA at high-service temperatures, as long as the WMA level STAT is used.

This paper was sponsored by TRB committee AFK30 Characteristics of Nonasphalt Components of Asphalt Paving Mixtures.

01550057

15-2676

English

19p

2015

Transportation Research Board 94th Annual Meeting

Digital/other

Figures; References; Tables

Asphalt concrete; Materials at high or low temperatures; Modulus of deformation; Styrene butadiene styrene; Temperature; Tensile properties; Tensile strength; Warm mix paving mixtures

Wheel tracking

Construction; Highways; Materials; I31: Bituminous Binders and Materials; I32: Concrete; I33: Other Materials used in Pavement Layers

Transportation Research Board Annual Meeting 2015 Paper #15-2676

TRIS, TRB, ATRI

Dec 30 2014 12:55PM