EVALUATION OF THE INDIRECT TENSILE STIFFNESS MODULUS TEST

In view to enhance in the field of characterization of asphalt mixes and to develop new test methods, RTE (the central laboratory of SCREG) has acquired a universal testing machine designed to conduct indirect tensile stiffness modulus testing. The interest of this technique is that it is time-saving compared to complex modulus and direct tension modulus tests. It also makes it possible to use both moulded or cored samples (cored samples are actually easier to make). It also facilitates the monitoring of work on site, because it is possible to measure the modulus directly on cores taken in situ from the pavement. Nevertheless, in spite of the standards' guidelines, there are still many ways to carry out the test using different loading signals and specimen sizes. It is also important to establish a possible correlation with other commonly used tests in France. We have studied a possible correlation with direct tension modulus measurement using the MAER (servo-controlled machine for rheological tests). A comparison has also been made between two completely different methods of modulus measurement in light of the fact that direct tension leads to a fairly homogenous stress distribution in samples, and does not require previous knowledge of Poisson's ratio. This article presents the first results obtained, mainly regarding hot mixes but also cold mixes. For the covering abstract see ITRD E117423.