Create smooth high-quality surfacing and roads with National Asphalt’s Hot Mix Asphalt (HMA) product, often referred to as tar. 100% Recyclable with quality accredited aggregate and bitumen combination, our product is easy to handle and apply, cooling down quickly – offering less traffic disruption. Aside from our numerous commercial fixed plants across South Africa, we also offer a mobile plant option to our clients. Mobility is our speciality offering plant production capabilities from 10t/hr to 160t/hr allowing us to tailor solutions for projects of all shapes and sizes.
Stone matrix asphalt (SMA) is a gap-graded HMA (Figure 1) that is designed to maximize deformation (rutting) resistance and durability by using a structural basis of stone-on-stone contact.
Bitumen Treated Base or the base course is the lower asphalt course/layers, below the surface and any levelling course. The base course provides the strength of the pavement and typically has an aggregate nominal particle size of 20mm.
The wearing course is the upper layer in roadway or runway. The main function of wearing course is to provide impervious layers so that entry of water to the base course can be prevented. Moreover, the entire traffic load is safely distributed over the base course.
PMB consists of bitumen blended with a synthetic polymer. PMBs are used to enhance the performance of binders on heavily trafficked or distressed pavement surfaces, often in adverse climatic conditions. Asphalt made with modified binders are more resistant to fatigue, thermal cracking, rutting, stripping, and temperature susceptibility than neat binders. Polymer modified binders tend to exhibit increased viscosity and elastic recovery.
Rubber modified binder has been shown to increase the fatigue resistance and durability of asphalt. Adding rubber crumb to the neat binder retards aging and oxidation of the resulting binder, which increases pavement life by lessening brittleness and cracking. Rubber modified asphalt binders can be used in open-graded asphalt mixtures, which have reduced hydroplaning, vehicle spray and reduced pavement noise.
EME is based on French technology Enrobé à Module Élevé developed in the 1980’s where low penetration – very hard – bitumen binders are used to produce very stiff asphalt layers. This high-performance and high-quality road construction material intended for use in heavy duty pavements due to its exceedingly high modulus. It is particularly suitable for pavements carrying large volumes of heavy vehicle.
