Performance Evaluation for Rutting and Moisture damage of Hot Asphalt Mixtures using High Percentage of Recycled Asphalt Pavement Material

This research examines how the addition of recycled asphalt pavement (RAP) changes the volumetric and mechanistic properties of asphalt mixtures. A Superpave® 19-mm mixture containing 0% RAP was the control for evaluating properties of mixes containing 15%, 25%, and 40% RAP. Two types of RAP were evaluated: a processed RAP and an unprocessed RAP (grindings). Testing included dynamic modulus in tension and compression, creep compliance in compression, and creep flow in compression. Dynamic modulus and creep compliance master curves were constructed with the use of the time–temperature superposition principle to describe the behavior of each mix over a range of temperatures. The voids in mineral aggregate (VMA) and voids filled with asphalt (VFA) of the RAP mixtures increased at the 25% and 40% levels, and there was also an influence of preheating time on the volumetric properties. The dynamic modulus of the processed RAP mixtures increased from the control to 15% RAP level, but the 25% and 40% RAP mixtures had dynamic modulus curves similar to that of the control mixture in both tension and compression. The creep compliance curves showed similar trends. A combination of gradation, asphalt content, and volumetric properties is likely the cause of these trends.

Download Full-text

Potential of Using Imidazoline in Recycled Asphalt Pavement

The Baltic Journal of Road and Bridge Engineering ◽

10.7250/bjrbe.2019-14.456 ◽

2019 ◽

Vol 14 (4) ◽

pp. 521-542

Author(s):

Robert Jurczak ◽

Paweł Mieczkowski ◽

Bartosz Budziński

Keyword(s):

Asphalt Concrete ◽

Asphalt Pavement ◽

Asphalt Mixtures ◽

Fatigue Performance ◽

Recycled Asphalt Pavement ◽

Recycled Asphalt ◽

Stiffness Modulus ◽

Optimum Content ◽

Environmental Considerations ◽

Freezing Temperatures

The environmental considerations need to be taken into account in any road resurfacing and upgrading project, for example, by reusing asphalt rubble for production of new pavement courses. Mixtures containing larger amounts of recycled asphalt pavement are improved by adding rejuvenator additives. The tests performed on the recycled asphalt mixtures containing lard imidazoline confirm the suitability of this agent for paving applications. Lard imidazoline was found to improve the stiffness modulus, fatigue performance and resistance to the action of water and freezing temperatures. The parameters obtained at the optimum content of additive complied with the criteria defined for virgin asphalt concrete and other mixtures of that kind.

Download Full-text

Performance Evaluation of Recycled Asphalt Pavement Materials and Cold Recycling Mixtures Designed with Vibratory Compaction Method

Applied Sciences ◽

10.3390/app9153167 ◽

2019 ◽

Vol 9 (15) ◽

pp. 3167

Author(s):

Yuhui Pi ◽

Zhe Li ◽

Yingxing Pi ◽

Zhe Huang ◽

Guangcan Li

Keyword(s):

Performance Evaluation ◽

Asphalt Pavement ◽

Heavy Duty ◽

Recycled Asphalt Pavement ◽

Recycled Asphalt ◽

Accelerated Curing ◽

Vibratory Compaction ◽

Cold Recycling ◽

Emulsified Asphalt ◽

Compaction Method

In this paper, the basic composition and performance evaluation of the recycled asphalt pavement (RAP) materials were firstly analyzed, and two methods were proposed to evaluate strength characteristics of RAP materials, including a triaxial method for the residual strength and the mortar cementing method for the strength of RAP lump. Then, the cold recycling technology was applied on RAP materials with emulsified asphalt by using vibratory compaction and heavy-duty compaction methods (Proctor compaction method), and the results showed that the maximum dry density obtained by heavy-duty compaction was closer to the actual situation. Finally, the effects of wetting water, emulsified asphalt dosage and curing conditions on the performance of the specimens were investigated. It was found that when the emulsified asphalt was mixed uniformly, whether or not to add the wetting water have almost no effect on the strength of the molded specimens. When the matrix asphalt content of the emulsified asphalt was 30%~60%, the water could be directly added to the cold recycling mixture. The intensity of accelerated curing for two days at 40 °C was approximately equal to that of natural curing for three days, while that of accelerated curing for three days at 40 °C was approximately equal to that of natural curing for seven days, which provided a basis for the short-term laboratory test.

Download Full-text