Additives for Asphalt – Types and Applications
Asphalt, which is commonly used for building and hardening road surfaces and is the main component of asphalt concrete mixtures, is often modified to maximize its quality. The technical properties of the applied mixture largely determine the resistance to rutting, fatigue cracking, and low-temperature cracking of road surfaces. The additives offered by Bitumer, presented below, are the most important asphalt modifiers that have a significant impact on the quality and durability of created asphalt surfaces.
The most important task of asphalt fluxes is to reduce the technological temperatures in the processes of production, embedding, and then compacting asphalt mixtures. Lowering these temperatures not only effectively influences the reduction of project costs but also allows for a decrease in the emission of harmful substances. In addition, asphalt fluxes allow for a reduction in the viscosity of mineral-asphalt mixtures during their production and embedding, and also cause a reduction in the temperature of fragility, which translates into the resistance of asphalt in winter during low temperatures.
Specialized adhesion agents, also called adhesion promoters, are used to increase the adhesion of asphalt and effectively reduce the surface tension between asphalt and aggregates. Their action increases the tightness, mechanical strength, and resistance to cracking of asphalt surfaces. The surface using the adhesion promoter additive is primarily more resistant to aging processes, which allows for a significant reduction in maintenance costs and repairs of road surfaces in the future.
Emulsifiers and Thickeners
Emulsifiers used for producing asphalt emulsions play a significant role in causing a decrease in the surface tension between the water phase and asphalt in a given emulsion. Additionally, they stabilize the resulting emulsion and improve the adhesion of asphalt to aggregates. Thickeners, on the other hand, have an impact on the consistency of the applied bituminous mass, which should be appropriately adjusted to the purposes and properties that the given surface must fulfill.
Cellulose fibers, which function as stabilizers and thickeners in mineral-asphalt mixtures, particularly in SMA mixtures used in binding layers, allow for a slight reduction in their thickness, thus reducing costs. Asphalt with the addition of cellulose fibers is lightweight and stable in transport, and also characterized by good distribution in the mixture and an increase in its fluidity.
Cationic latex is used in road surface construction to increase the strength, viscosity, and ductility of mineral-asphalt mixtures. This type of latex greatly improves the quality of the asphalt, its softening temperature, low-temperature flexibility, and resistance to aging during later use. It has strong rapid binding properties and enhances the flexibility of the surface even at very low temperatures. Cationic latex is ideal for creating thin layers in the construction of cold asphalt surfaces and can also be successfully applied using hot methods.
When planning the composition and modifications of mineral-asphalt mixtures for road construction, maximum resistance to various weather conditions and damage that may occur not only during construction but also during many years of road use should be ensured. Some of the important characteristics that the mixture should have include resistance to permanent deformation, reflective cracking, and thermal cracking, and, most importantly, resistance to water and aging of the surface, which is undoubtedly a problem for builders and engineers. Proper additives for asphalt offered by a reliable company with experience in road construction technology and road systems will allow for the installation of a surface that will not require constant repairs, which will significantly reduce the costs of its later operation.
One of the fastest developing directions in asphalt surfaces are the additives for asphalt binders and mineral-asphalt mixtures. The operational properties of mineral-asphalt mixtures and the extension of the service life of road surfaces require the use of modified asphalts. Asphalt surfaces in which modified or highly modified asphalts have been used are significantly more durable than those made with road asphalts. The article provides examples of modern solutions used in asphalt surface technology in Poland and worldwide based on the study of mineral-asphalt mixtures