Viscoelastic study of fresh and aged hot-mix asphalt with sintered calcined clay aggregate

ABSTRACT

The mechanical behavior of flexible pavement asphalt coatings, composed by bituminous binder, depends on several factors, among them: compaction process, temperature and loading application rate. Several reactions occur on the main constituents of these asphalt mixtures, so as oxidation, physical hardening and loss of volatiles. In the case of the asphalt binder, aging increases viscosity, associated to a decrease in the penetration and loss of its binding properties. In particular, the consistency achieved with the time leads to an increase of the stiffness. This paper aims to study the mechanical behavior of fresh and aged asphalt mixtures manufactured with Sinterized Calcined Clay Aggregate (SCCA) by four-point bending tests. The effect of the compaction process in the prismatic specimens modulus |E*| was determined, so as the influence of the asphalt binder aging. The results presented a drop of up to 81.1% in |E*| values under the selected series of temperatures and frequencies. The experimental data was analyzed by means of the Euler-Bernoulli Theory generalized for viscoelastic materials with 4PB representative dynamic loading. The theoretical modeling compatibility was pronounced for both searched compositions (fresh and aged), considering the curve fitting achieved, represented by the coefficients of determination (R²) that were acquired.

Keywords
Aging; Dynamic modulus; Four-point bending; Calcined clay aggregate