Emulsions for Road Paving

Road paving. This includes bitumen, cutbacks and fluxed bitumen as well as emulsions. Each of these products is subject to very special application techniques. This list is completed by the use of poured asphalt, even though this product is better suited to smaller surfaces sidewalks, courts, etc., than to pavements. Since the middle of the 1980 s, air-blown bitumen is no longer used for road construction. 

Asphalt emulsions are used in road paving for the production of a smooth, water-repellant surface. First, an asphalt O/W emulsion is formulated that has sufficiently low viscosity to be easy to handle and apply, which has sufficient stability to survive transportation, brief periods of storage and the application process itself. The emulsion needs to be able to shear thin during application and... 

Asphalt emulsions are used in road paving for the production of a smooth, water-repellant surface. First, an asphalt O/W emulsion is formulated, which has sufficiently low viscosity to be easy to handle and apply, and which has sufficient stability to survive transportation, brief periods of storage, and the application process itself. The emulsion needs to be able to shear thin during application, and then break quickly when it contacts the aggregate. The asphalt emulsions are usually 40-70% bitumen and stabilized either by natural naphthenic surfactants released by treatment with alkali (for a somewhat similar situation involving bitumen processing see also [64]), or else by the addition of anionic or cationic surfactant [106]. Emulsified asphalt can be applied to gravel or rock even when wet [1,20,105,106]. 

Road oils are Hquid asphalt materials iatended for easy appHcation to earth roads. They provide a strong base or a hard surface and maintain a satisfactory passage for light traffic. Liquid road oils, cutbacks, and emulsions are of recent date, but the use of asphaltic soHds for paving goes back to the European practices of the early 1800s. 

The principal use of coal tar in paving is as a seal coat to bitumen paving. Asphalt for paving comes in several forms determined by the intended application, ie, straight asphalts called asphalt cements (AC), asphalt emulsions, cutback asphalts, and road oils. 

According to CEN EN 13808 (2013), the required properties of a cationic emulsion suitable for use in the construction and maintenance of roads, airfields and other paved areas are selected from the classes shown in Table 3.13. Additionally, the technical requirements and performance of the residual, recovered, stabilised and aged binder from the cationic bituminous emulsion is selected from the classes shown in Table 3.14. 

Chip seal Loose chips from a freshly paved road are the major safety concern for chip seal operation, and several attempts were reported in the literature to develop a laboratory procedure to simulate the field experience. A modified fretting test (also know as the abrasion cohesion test Esso, ACTE) appears to be the most success-fid [26, 27]. In this test a known amount of CRS-2 asphalt emulsion and aggregates are spread on a roofing felt, and then rolled with a 301 rabber roller. The sample is subjected to the shearing action of a horizontal steam-hose, which is attached to a Hobart sun and planet mixer, and the percentage of retained chips is recorded as a function of curing time. 

Asphalt roads account nearly 95 % (3 300 000 km) of the paved roads in the US Addition of as little as 2-3 % of polymers in the asphalt improves mtting resistance, and prevents premature fatigue and cold fracture crack formation. The latex can be used for both hot mix and emulsion based paving. Recent studies [33] on eco-efficiency analysis clearly demonstrate economical and ecological advantages of the asphalt emulsion based microsurfacing for preventive maintenance. 

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