Determination of master curves for asphalt mixtures by means of IT-CY tests
The concept of ecologically conscious and energy saving roads must be expanded to the performance of the asphalt mixtures as well as to the test related to it. This paper investigates the tests focusing on a better description of the behaviour of asphalts as well as on a deeper revelation of the impact of different compositions. Based on the international experiences the recording of the asphalt´s complex module over the entire temperature range by the determination and evaluation of the mater-curves appeared as a possible solution for more precise description of the asphalt behaviour.
Performance Evaluation of Warm Mix Asphalt Mixtures with Recycled Asphalt Pavement
Warm mix asphalt (WMA) technology provides not only the production of asphalt pavement at a lower temperature than the temperature maintained in Hot Mix Asphalt (HMA) but also encourages the utilization of Recycled Asphalt Pavement (RAP) and therefore saves energy and nonrenewable resources as well as reduces emissions and fuel consumption. This paper describes the feasibility of utilizing four different WMA additives (organic, chemical, synthetic zeolite and natural zeolite) with different rates of RAP. Following the determination of optimum RAP content corresponding to each WMA additive, Marshall analysis, indirect tensile stiffness modulus and fatigue behavior of HMA and WMA involving RAP were analyzed and compared with control specimens. Hamburg wheel tracking device was also utilized to evaluate the permanent deformation characteristics of mixtures containing optimum RAP content.
Interpretation of dynamic mechanical test data for paving grade asphalt cements
Dynamic mechanical analysis, and other methods of rheological testing, have been used for many years on asphalt cement. Unfortunately, there currently exists some confusion over the interpretation of dynamic mechanical data on asphalt cements. In order to clarify appropriate methods of interpreting rheological data on paving grade asphalts, test data for a number of asphalt cements having widely different properties must be analyzed in light of rheological theory and appropriate mathematical models. The purpose of this paper is to describe various useful techniques for interpreting viscoelastic data on asphalt cements. Dynamic mechanical test data is emphasized, although many of the principles presented apply equally well to other types of rheological data.