Why should pre-coated chippings be added to the hot rolled asphalt surface course?

Why should pre-coated chippings be added to the hot rolled asphalt surface course?

Pre-coated chippings are highly resistant to polishing which are rolled into and form part of an HRA surface course.

What are pre-coated chippings?

Pre-coated chippings are intended for use in hot rolled asphalt surfaces, increasing the skid resistance and durability of the road surface. These chippings have a 20mm aggregate size and 65+ PSV (polished stone value).

What is hot rolled asphalt?

Hot Rolled Asphalt (HRA) is a dense mixture of mineral aggregate, sand, filler and bitumen that complies with EN 13108 and the TII Specification for Road Works. There is a high proportion of sand in the mix resulting in a low percentage of air voids when it is compacted.

What is the difference between SMA and HRA?

The bitumen content, whilst higher than for SMA is less than used for HRA. The continuous aggregate grading gives high mechanical stability due to the aggregate particle interlock and as such is a more sensible material altogether than HRA which is a gap graded mix more akin to a plum pudding.

What is warm mix asphalt?

Warm Mix Asphalt (WMA) is the generic term for a variety of technologies that allow producers of Hot Mix Asphalt (HMA) pavement material to lower temperatures at which the material is mixed and placed on the road. It is a proven a technology that can: Reduce paving costs.

What does HRA 35 14 mean?

HRA 35/14 F surf des 40/60. This means 35% coarse aggregate of 14mm nominal size in the mixture. “F” represents Fine grading.

What types of asphalt are there?

There are three main types of asphalt: Hot Asphalt, MC Cold Mix, and UPM. There are also different varieties of these asphalts for summer and winter use.

What is the difference between Bitmac and asphalt?

Bitmac is manufactured by removing the tar and replacing it with bitumen. This creates a new surface which is more similar to asphalt. However the difference between bitumen and asphalt is that there is a far greater concentration of sand and filler in bitmac.

What is 10mm SMA?

S.M.A. Pave® is a HAPAS approved thin surface course material available in 14mm and 10mm nominal size aggregates. It has been specifically designed for use in heavily trafficked, high speed highways. This product is only available to approved contractors to ensure its optimum performance. BENEFITS.

What is the difference between warm mix asphalt and hot mix asphalt?

Warm Mix Asphalt is produced and mixed at temperatures roughly between 100 and 150 °C. Hot Mix Asphalt is produced and mixed at temperatures roughly between 120 and 190 °C The production temperatures of Hot Mix Asphalt depend on the bitumen used.