Mechanisms of Asphalt Blistering on Concrete Bridges

ABSTRACT: Blistering is a major problem in asphalt-covered concrete struc­tures, such as multi-storage parking buildings, built-up roofs, tunnels, pedes­trian areas, or concrete bridge decks. In this particular research, a linear viscoelastic finite-element model is developed to simulate time-dependent blister growth in an asphalt layer under uniformly applied pressure with and without temperature and pressure fluctuation. Indirect tensile tests on mastic asphalt (MA) are performed at three different temperatures to characterize and determine the material properties for the model. A three-dimensional thick-plate axisymmetric finite-element model is developed using ABAQUS with linear viscoelastic properties and validated with closed-form solution from first-order shear-deformation theory for thick plates. Elastic-viscoelastic analogy is used to find an analytic solution for the time-dependent deflection of the blister. In addition, the blister test is conducted on different samples of MA in the laboratory and digital image correlation measurement technique is used to capture the three-dimensional vertical deflection of the MA with time. Finally, the results from image correlation are compared with the finite-ele­ment simulation and thick-plate theory analytic solution. The finite-element model simulation shows that the daily temperature variations may have a

significant influence on blister growth in asphalt pavements. It is found that the blister can grow continuously under repeated loading conditions over sub­sequent days. The study concludes that temperature fluctuation in the blister has more influence on blister growth than fluctuation of the pressure inside the blister.

KEYWORDS: blister growth, indirect tensile test, finite-element method, master curve, ABAQUS™, Prony series, sigmoidal function, creep, relaxa­tion, closed-form solution