Bitumen is ‘cutback’ by adding controlled amounts of petroleum distillates such as kerosene.
This is done to reduce the viscosity of the bitumen temporarily so it can penetrate pavements more effectively or to allow spraying at temperatures that are too cold for successful sprayed sealing with neat bitumen. The materials used to cutback bitumen will evaporate after application to leave the remaining material similar in hardness to the original bitumen.
The process of priming involves applying a low viscosity binder to a prepared but usually unbound aggregate base. It is intended to be absorbed by the top layers of the base and provide a surface more easily ‘wetted’ by a subsequent bituminous covering. The primer will be able to carry traffic for a short time (although this practice is uncommon) and help control dust. Generally, primers are applied at rates between 0.5 and 1.4 L/m2. Cutback bitumens suitable for priming are also used for tack coats, which are applied to an underlying surface to help with the adhesion of subsequent asphalt layer. A typical application rate is between 0.2 and 0.4 L/m2.
|Application||Puma Cutback Products||Australian Standard Guide||Pavement Surface Type Suitability|
|Priming & Tack Coating||Puma Bitumen AMC00||AMC00||Low Porosity Surfaces|
|Puma Bitumen AMC0||AMC0||Medium Porosity Surfaces|
|Puma Bitumen AMC1||AMC1||High Porosity Surfaces|
|Primer Sealing & Pre-mixing||Puma Bitumen AMC2||AMC2||Low Porosity Surfaces|
|Puma Bitumen AMC3||AMC3||Medium Porosity Surfaces|
|Puma Bitumen AMC4||AMC4||High Porosity Surfaces|
|Puma Bitumen AMC5||AMC5|
|Sealing||Puma Bitumen AMC6||AMC6|
|Puma Bitumen AMC7||AMC7|
Where temperatures are too cool for an effective priming operation, or where traffic is likely to upset a primed surface before the final seal can be sprayed, a primer seal can be used to give adequate protection of the pavement for periods of up to 6 to 12 months. Cutback bitumens suitable for primer sealing can also be used in the manufacture of pre-mix asphalt, which is used in patch repairs.
Cutback bitumens are used extensively in sprayed sealing applications, particularly in cooler weather where they provide improved initial stone retention due to their lower viscosity. Typically, a single application of the appropriate cutback bitumen is sprayed onto the primed pavement onto which aggregate is spread.
Puma Bitumen cutbacks are manufactured to comply with the requirements of Australian Standard AS 2157 Cutback bitumen.
|Grade||Viscosity at 60°C, Pa.s||Flashpoint, °C||Maximum Storage Temperatures, °C*||Application Temperature, °C**|
|Puma Bitumen Cutback AMC00||0.008 - 0.016||> 38||100||10 - 30|
|Puma Bitumen Cutback AMC0||0.025 - 0.05||> 38||110||35 - 55|
|Puma Bitumen Cutback AMC1||0.06 -0.12||> 38||120||60 - 80|
|Puma Bitumen Cutback AMC2||0.22 - 0.44||> 38||140||75 - 110|
|Puma Bitumen Cutback AMC3||0.55 - 1.1||> 38||160||95 - 115|
|Puma Bitumen Cutback AMC4||2.0 - 4.0||> 38||170||110 - 135|
|Puma Bitumen Cutback AMC5||5.5 - 11.0||> 50||175||120- 150|
|Puma Bitumen Cutback AMC6||13.0 - 26.0||> 50||180||135 - 160|
|Puma Bitumen Cutback AMC7||43.0 - 86.0||> 50||185||150 - 175|
*Maximum temperatures for storage periods of up to 24 hours.
**The application temperatures shown in the above table follow standards which have been generally accepted by the industry. They should be followed when the product needs to be reheated. In some field situations cutbacks are sprayed at temperatures above these recommendations with good results, however adequate safety measures must be in place.
To ensure hot bitumen is used in a safe and efficient manner the following safety precautions must be followed:
Cutbacks are sometimes used at a temperature above their flashpoint, so care must be taken regarding the product’s flammability. Ensure personnel are well trained in the correct handling procedures. For further information on product health and safety information, please refer to the appropriate material safety data sheet (MSDS) available on the Puma Bitumen website.
Puma Bitumen is recognised nationally for its proven track record in delivering products of consistently high quality.
Every day our products perform under the most diverse and demanding road conditions in Australia.
This is attributable to a combination of our unique product technology, comprehensive quality assurance programs, operational efficiency and sophisticated production processes – all supported by our highly skilled and experienced staff.
We maintain an in-house national technical centre in Melbourne which focuses on R&D, as well as providing technical expertise and support to our customers throughout Australia.
Our team of technical specialists is dedicated to ensuring our products are thoroughly tested at every stage – from the selection of crude oil at the start of the production process, right through to delivery.
Our product stewardship and rigorous quality management practices reflect our commitment to delivering the highest quality products that perform on the road.
Our commitment to quality is recognised by our accreditation to Australian Standard AS/NZS 9001.