Research into the low temperature cracking in asphalt pavements is an important priority in asphalt laboratories worldwide. In such laboratories the low temperature cracking process is simulated on asphalt samples using several different types of tests. Due to the fact that the resistance of asphalt to low temperature cracking depends mainly on the used bitumen, it is assumed that this process can be indirectly predicted with knowledge about the realistic low temperature properties of bitumen. For many years the properties of bitumen at low temperatures have been determined based on the Fraass fracture temperatures. Since the Fraass breaking point test has several shortcomings, additional parameters like stiffness and creep rate were introduced in the Bending Beam Rheometer (BBR) method, which has been standardized but it is still not widely used. The characteristics of B 70/100, which is frequently used in Slovenia for asphalt production, has not been yet tested by this method.
In the master’s thesis six samples of bitumen B 70/100 were extensively tested. The purpose of the study was to determine the impact of aging on the paving grade bitumen B 70/100 used in our region, and to propose criteria for bitumen quality based on evaluation of obtained test results. On neat bitumen the usual scope of bitumen tests (R&B, Penetration, Fraass) was performed as well as BBR and Dynamic Shear Rheometer (DSR) tests. These bitumens have been artificially aged with Rolling Thin Film Oven Test (RTFOT) method and all tests were repeated on short term aged bitumens. In the last step the six bitumens have been artificially aged with RTFOT and Pressure Ageing Vessel (PAV) method and then retested. In the thesis, the sensitivity to laboratory aging for six different samples of B 70/100 bitumens is presented and analyzed. The lowest and the highest ambient temperatures suitable for the six samples of B 70/100 were determined.
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