on the combined effect of moisture diffusion & cyclic pore pressure generation in ac
DESCRIPTION
In this paper, a simple moisture conditioning protocol which attempts to distinguish the contributions of long- and short-term moisture damage i.e. moisture diffusion and cyclic pore pressure generation in asphalt mixtures is presented. The capability of the proposed protocol to rank various asphalt mixtures of known field performance for their short- and long-term sensitivity to moisture is evaluated on the basis of the Tensile Strength Ratio. Asphalt specimens with different types of aggregates and asphalt binders were conditioned by various combinations of water bath immersion and cyclic pore pressures by means of the Moisture Induced Sensitivity Tester. The results show that the proposed conditioning protocol can be used to evaluate the moisture susceptibility of asphalt mixtures and distinguish among mixtures with different moisture damage susceptibility. In addition, it is shown that the use of cyclic pore pressures has a significant effect and can be used as an accelerated moisture conditioning procedure.TRANSCRIPT
On the Combined Effect of Moisture Diffusion & Cyclic Pore Pressure Generation in AC
Aikaterini Varveri, Sandra Erkens & Tom Scarpas Pavement Engineering, Delft University of Technology
Stavros Avgerinopoulos Faculty of Engineering, De Montfort University
CROW Infradagen 2014, The Netherlands, June 18-19, 2014
Moisture damage in AC
Moisture diffusion
Advective transport
Wheel loading
Pumping action
CO
UP
LIN
G Degradation of the cohesive strength
of the asphalt binder
Loss of the adhesion bond between aggregate & asphalt binder
Long- and short- term processes
Moisture diffusion
Pumping action
Moisture Induced Sensitivity Tester (MIST)
Moisture conditioning protocol
Determination of bath conditioning time
Dt
Fick’s law
Determination of MIST cycles
Samples preparation
Aggregate Type
Bitumen Type
Pen 70/100
Moderately Polymer Modified
(Pen 50/80)
Highly Polymer Modified
(Pen 65/105)
Sandstone SP SM SH
Granite GP GM GH
Tensile Strength Ratio (TSR)
Long- and short-term contribution
Tensile strength degradation
SH
SP
SM
GH
GM
GP
Long- and short-term contribution
Conclusions
Specifically mixtures produced with: - Sandstone aggregates show better moisture damage performance compared to granite mixtures. - polymer modified binders show lower susceptibility to moisture damage compared to those using conventional binders. - Softer bitumen types demonstrate higher moisture damage sensitivity.
The protocol enables: - The evaluation of the moisture resistance of asphalt mixtures and distinguishing mixtures with different moisture damage susceptibility. - The quantification of the individual short- and long-term moisture damage contribution to the overall specimen damage.
Aikaterini Varveri, Sandra Erkens & Tom Scarpas Pavement Engineering, Delft University of Technology
Stavros Avgerinopoulos Faculty of Engineering, De Montfort University
CROW Infradagen 2014, The Netherlands, June 18-19, 2014
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