Investigation Of Comparability Of TSRST And SCB Cracking Tests For Evaluation Of Low-Temperature Properties In Asphalt Mixtures And Use In Quality Control

Abstract

Mix design procedure for asphalt mixtures in the Baltic region requires to ensure resistance to low temperatures due to climatic conditions. Thermal Stress Restrained Specimen Test (TSRST) has been considered as the most precise direct test method to determine the thermal behaviour of asphalt mixtures. As the TSRST test is time-consuming and the equipment is much more expensive, therefore the possibility to use Semi-Circular Bending (SCB) as a preliminary test was evaluated and the potential threshold was recommended. This study presents the evaluation of low-temperature properties with SCB and TSRST methods and the test suitability assessment for use in quality control. The supplementary rating was made by analysing Fraass breaking point test results of asphalt binders. In total 36 different asphalt samples were tested to investigate fracture test methods and to assess the influence of bitumen type and composition on resistance to low-temperature cracking. The results displayed an acceptable correlation between both test methods that allow using SCB for pre-screening purposes. At the same time, the results indicated that the type of used bitumen has a crucial influence on asphalt mixtures resistance to low-temperature cracking.