INTERNATIONAL CONGRESS ON RECENT ADVANCES IN SCIENCES AND TECHNOLOGY - Kuala Lumpur - Malaysia (2019-02-20)

Rheological properties of mastic mortar depending on petrographic origin of filler particles
One of the basic parameters for estimating the properties and quality of asphalt mixtures is the performance behaviour of the asphalt binder. It is necessary to consider that the resulting binder in these mixtures is a mastic mortar. It is a mixture of asphalt binder and very fine filler particles (aggregate particles of less than 0.063 mm). The properties of mastic mortar can significantly influence the rheological behaviour of the asphalt mixture and also the viscoelastic behaviour of compacted asphalt layers including resistance to cracking. In spite of this, the number of scientific works dealing with this problem in a comprehensive way is very limited. The aim of this work is to describe the basic rheological behaviour of these mastic materials using a dynamic shear rheometer, especially in relation to the petrographic origin of the filler grains. Therefore, 14 types of fillers were mixed with paving grade bitumen 70/100 in different ratios. The petrological composition of the fillers was determined by powder X ray diffraction analysis. Attention was paid to the influence of the presence of mica (especially muscovite and biotite) on the properties of fillers and mastic mortars. The properties of the fillers were evaluated by the determination of the voids of dry compacted filler (Rigden voids) and the delta ring and ball test. The influence of petrographic origin of the rock on the properties of the mastic mortar was demonstrated using various rheological types of tests. Especially multiple stress creep and recovery test (MSCR test) test and oscillatory shear test at 60 °C in a dynamic shear rheometer were performed on these mastic mortars. It can be seen from the results that it is advantageous to use a dynamic shear rheometer in oscillatory or creep mode for the evaluation of the properties of mastic materials. The petrographic origin of the filler (at approximately the same particle size distribution) greatly affects its stiffening effect. The limestone filler stiffened the asphalt binder at least and the reference materials containing the high portion of mica stiffened the asphalt binder the most.
Dr. Ondrej Dasek, Dr. Petr Hyzl, Assoc. Prof. Dusan Stehlik, Dr. Svatopluk Stoklasek