DURABILITY OF POROUS ASPHALT PAVEMENT

Ahmed Al-Kaissi, Zainab; Ghalib Mashkoor, Omar

	DURABILITY OF POROUS ASPHALT PAVEMENT
Journal of Engineering and Sustainable Development
Article 1, Volume 20, Issue 4, 2016, Pages 53-70
Authors
Zainab Ahmed Al-Kaissi; Omar Ghalib Mashkoor
Abstract
This work describes a research study for evaluating the durability performance of open-graded asphalt materials in terms of accelerated aging, moisture damage and permanent deformation. Such asphalt mixes have high porosity, which offers significantly better drainage properties than normal mix designs. However, these materials also exhibit poor durability and strength limiting their use in pavement application, to remedy this, fiber and/or polymer binder modifiers have been proposed. samples were prepared with and without the modifiers using Marshall mix procedures and slabs (approximately 1000 samples for Marshall test with 20 slabs for wheel track test (Dyna-Track) and were experimentally tested using various conditions ( short and long term aging ) and standardized testing procedures including wheel track test for rutting, falling-head test for permeability , cantabro abrasion test for particle loss resistance and indirect tensile test for strength. In general, the results indicate that the introduction of fiber modifiers leads to minor improvement in strength characteristics of the samples, while contributing to significant reduction in permeability. On the other hand, the introduction of polymer modifiers nearly doubled both the strength and permeability and also increased the air voids. However, when polymer fiber is used (6% is the best percent of polymer modifiers), additional strength improvement is observed of 39,17and 8% for Control, short and long term aging respectively at 60C, but the permeability increase is not as large as that with polymer modifier alone of 10,12and 19% for Control, short and long term aging respectively. Consequently, the results indicate that, the best strength and permeability characteristics can be achieved by introducing only polymer modifier in the mix. Also, the effects of elevated temperature are investigated and it is found to have significant influence on the strength and permeability characteristics of the mixture.The second approach is testing the slabs as the same as the previous testing conditions. The resulting increase in the polypropylene additive increases the number of passes which reaches the same value of rutting (11.75mm of rutting at1000 passes). In case of long and short term aging increase. the number of passes which reach the same value of rutting (value in the case of the control) is increased and increases in the asphalt content decreases the number of passes which reach the same value of rutting (11.35,9.4mm of rutting at1000 passes) for short and long term aging for CM model.
Keywords
porous asphalt; permeability; Open Graded Fraction Courses; Rutting; Durability

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