Experimental Analysis on Material Properties for Buton Rock Asphalt and Its Modified Asphalt

摘要

To reveal the modification mechanism of Buton rock asphalt (BRA), limestone mineral (LM), and pure natural asphalt (NA) which are the two major components of BRA were obtained using extraction and combustion methods. Then a series of physicochemical and performance experiments were conducted to analyze the properties of BRA, LM, NA, and BRA modified asphalt. The properties of mineral powder and common road petroleum asphalt were also tested for the purpose of comparison. The results show that LM can be used to replace the mineral powder of asphalt mixture due to its large specific surface area and porous limestone structure. NA is a hard and natural asphalt whose contents of asphaltene and aromatic ring structure are high, and its asphaltene and colloid have large molecular weight. NA has stable colloidal structure and poor rheological properties as its nitrogen, sulfur, and other mixed elements are in the form of functional groups. Strong coating and adsorption effects exist between NA and LM, leading to the stable granular structure of BRA. Meanwhile, NA shows good and stable physical compatibility with petroleum asphalt, such that the excellent properties of BRA can be inherited into the modified asphalt. Mixed BRA into common petroleum asphalt, BRA can effectively improve resistance of its modified asphalt to high temperature, spalling, deformation, aging, and temperature sensitivity, etc. Therefore, BRA is an excellent natural asphalt modifier and can be popularized and applied in highway engineering.