New Alumosilicate Fillers Based on Sedimentary Rocks for Asphalt Concrete
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New Alumosilicate Fillers Based on Sedimentary Rocks for Asphalt Concrete Valeria Strokova1, Mikhail Lebedev1, Irina Potapova1 and Konstantin Sobolev2, 1 The Belgorod State Technological University named after V.G. Shoukhov, Belgorod, Russia 2 Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, Milwaukee, USA ABSTRACT Asphalt concrete is the most common material for highway and motorway construction. The quality of asphalt is determined, to a large extent, by properties of asphalt binder. Fillers, which are mineral powders from carbonate rocks and aggregates fines, such as limestone and dolomite, are often used in the composition of bitumen mastics affecting the performance of asphalt. This article explores the feasibility of using the fines of aluminosilicate sedimentary rocks as fillers. These materials are composed of clay minerals, which change their properties upon the contact with water. Normally, the use of such fillers is restricted because of poor water resistance and swelling of asphalt concrete. In order to improve the performance of these fillers, the thermal modification at moderate temperatures of 500–600 oC has been proposed. Such treatment provides sufficient structural stability of obtained materials and results in the reduction of water absorption of asphalt, improved water resistance (up to 2.5 times) and also, in reduced swelling (up to 9 times). It has been demonstrated that improvement in the filler performance can be achieved by a heat treatment. Such treatment induces changes in the mineral composition and converts the structure of clay minerals into the frame structure of zeolite, as confirmed by X-ray diffraction and infrared spectroscopy. Due to thermal treatment, there is a change in the acid-base properties of the surface of the filler, which is reflected in the profiles of the main adsorption centers. As a result, due to chemisorption, the modified aluminosilicate fillers are able to interact with bitumen. The application of new filler materials in asphalt concrete enables to enhance the performance. INTRODUCTION The construction of asphalt pavements in Russia requires the application of a range of mineral materials such as rocks and waste products [1, 2]. The expansion of raw materials supply is possible by the use of large deposits of sedimentary rocks [3, 4]. Weathering and sedimentation genesis make these materials the most complex polymineral systems, based on quartz and silica-aluminates. However, these materials may demonstrate unstable properties, which complicate their use in the production of building materials. Still, these materials can be used as mineral fillers for asphalt binders and asphalt concrete. Changes in the crystal and chemical characteristics of clayly soils and improvement of physical and mechanical properties can be facilitated by modification, activation, [4–6] and thermal modification is proposed as the most appropriate approach [11–13]. According to available literature [4–8], the thermal treatment improves the pozzolanic prope
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