The use of bitumen wax compositions as pavers and coverants for various surfaces such as roads and airports is known. Such compositions contain a mixture of aggregate and asphalt in a specified proportion and are generally laid and compacted while hot to provide a dense and durable surface.
Fuels such as diesel and gasoline have a damaging effect on asphalt. These fuels tend to dissolve or soften the bituminous components of bituminous surfaces. Thus, over time, the aggregate composition of such a surface tends to become less well combined, and thus the surface tends to disintegrate. Suitable synthetic waxes include hydrocarbon waxes, such as polyethylene waxes, and better waxes obtained in the fee-tropsch process. Waxes with functional groups, such as chemically modified hydrocarbon waxes, and waxy esters and amides, may also be used.
In many applications, asphalt provides aggregates with sufficient durability and adhesion. However, for heavy-duty applications, additives can be added to the asphalt to improve its mechanical properties. To this end, various additives have been proposed, including ethylene-vinyl acetate copolymers, styrene and conjugated diene random copolymers or block copolymers (such as SBS copolymers).
Recently, synthetic waxes containing synthetic aliphatic hydrocarbons have also been used in asphalt mixtures. Compared with wax-free asphalt, this asphalt-wax mixture is more resistant to deformation under high load.
Fuels such as diesel and gasoline have a devastating effect on asphalt. These fuels tend to dissolve or soften the asphalt components on the asphalt surface. Therefore, over time, the aggregate components of such a surface tend to become less well-bonded, so the surface tends to disintegrate.
Surprisingly, we have now found that wax can be used to improve the fuel resistance of asphalt.
Petroleum wax and synthetic wax, especially suitable for the composition of asphalt wax. Within the range of 50 °C, 60-150 °C and 60-120 °C, their softening point and melting point are better. Examples of petroleum waxes include paraffin waxes and microcrystalline waxes. Such waxes are well known and are usually obtained from crude oil or petroleum distillates using known techniques.
Paraffin is a coarse-grained product, usually solid at room temperature (25 degrees Celsius). Microcrystalline waxes also tend to be solid at room temperature. However, in addition to being obtained from petroleum distillates, these waxes can also be found naturally, for example, in the form of ground wax. The ground wax can be refined and bleached to make ceramsite wax and can also be used as a fuel additive.
Suitable synthetic waxes include hydrocarbon waxes, such as polyethylene waxes, and better waxes obtained during the Fischer-Tropsch process. It is also possible to use waxes with functional groups, such as chemically modified hydrocarbon waxes, wax esters and amides.