Abstract
The paper presents the results of a study of the mechanism for reducing the moisture resistance of sulfur-extended asphalt concrete. It is shown that a decrease in moisture resistance occurs due to the occurrence of chemical and physical processes. At the same time, it was found that during the manufacture of sulfur-bitumen composites, toxic gases H2S and SO2 are formed, which are capable of interacting with a mineral filler, as well as the interaction of sulfur with a mineral powder with the formation of sulfur-containing water-soluble salts, the extraction of which leads to a decrease in the moisture resistance of sulfur-bitumen materials. The change in the rate of leaching of these substances from the composite is due to the physical process caused by the crystallization of sulfur and the formation of a capillary structure, which significantly increases the rate of leaching of calcium and magnesium salts, which are products of dissolution or hydrolytic decomposition of water-soluble products of the interaction of sulfur, H2S and SO2 gases with calcium and magnesium carbonates. The intensity of chemical and physical processes intensifies with an increase in the amount of sulfur in sulfur-bitumen materials.
Highlights
The authors of works [1,2,3,4,5,6] have shown that the use of sulfur as a modifier for asphalt concrete is a promising direction, allowing the expansion of the temperature range of operation of asphalt concrete pavements in the area of high positive temperatures
In works [5,6,7] it is shown that the introduction of sulfur provides a decrease in the amount of bitumen in the asphalt concrete mixture, as well as a decrease in the temperature of preparation and laying The use of sulfur improves the operational properties of sulfur asphalt concrete (SEA) and the technological properties of the mixture
The partial solubility of bitumen in the bitumen melt in an amount up to 10% of the amount of introduced sulfur has been established, the remaining sulfur forms a dispersed system such as an emulsion, in which the dispersed phase is molten sulfur droplets, and the dispersion medium is a melt of petroleum bitumen [10]. (Asphalt concrete with the addition of sulfur received the name sulfur-extended asphalt concrete- SEA [10])
Summary
The authors of works [1,2,3,4,5,6] have shown that the use of sulfur as a modifier for asphalt concrete is a promising direction, allowing the expansion of the temperature range of operation of asphalt concrete pavements in the area of high positive temperatures. The processes of crystallization of sulfur in the volume of the sulfur-bitumen binder and the formation of capillaries that increase the permeability of asphalt concrete for liquid media (physical hypothesis).
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