FAQs
1. WHAT IS ASPHALT?
Essentially, asphalt is a combination of aggregate (crushed rock and / or sand) and bitumen (derived from crude oil). Asphalt may also incorporate additives to improve performance (e.g. fibres, wax, polymers and pigments). Asphalt is commonly used in the construction of roads, pathways, car parks, driveways and play areas. Typically asphalt is black, but it may also be red, green, blue and golden.
2. WHAT ARE THE DIFFERENT TYPES OF ASPHALT?
Commonly used asphalts in the UK are asphalt concretes (previously termed ‘bituminous macadams’ or ‘bitmacs’), hot rolled asphalts (HRAs), and stone mastic asphalts (SMAs). Asphalts can further be grouped into roadbase, binder and surface courses, each providing a different function in flexible pavement construction.
3. WHAT DO THE DIFFERENT GRADES OF BITUMEN REFER TO?
Bitumen is graded on stiffness (penetration in tenths of a mm of a 100g needle dropped onto a bitumen sample for 5 seconds at 25°C and softening point). Lower ‘pen’ value bitumens are therefore stiffer (i.e. 40/60 pen is stiffer than 160/220 pen). Lower ‘pen’ bitumens also have higher softening temperatures compared to higher ‘pen’ grades. Commonly used bitumen grades in the UK are 40/60 pen, 70/100 pen, 100/150 pen, and 160/220 pen. 100/150 pen bitumen is the preferred grade for most applications in the UK, although 40/60 is used for heavily trafficked roads, and 160/220 is often used for hand lay work as it is easier to apply.
4. WHAT TYPE OF ASPHALT DO I REQUIRE?
This will depend on the application which it is to be used. Our Sales Department will be able to offer advice on the most suitable types of asphalt for your requirement.
5. WHAT ARE PROPRIETARY MATERIALS AND WHY CHOOSE THESE OVER ‘NORMAL’ ASPHALT MATERIALS?
The Proprietary Materials offered by Breedon Group are extensively designed and rigorously tested to exceed the performances of traditionally used asphalts in specific applications. Our Proprietary Materials often include additives to achieve these high levels of operation.
6. HOW MUCH ASPHALT DO I NEED?
As a guide, please refer to our Material Calculator.
7. WHAT DEPTH SHOULD I LAY ASPHALT?
This can vary depending on the site. As a rule of thumb however, the depth should be at least 4 times the dimension of the largest nominal size in the mix for surface course (i.e. 40mm depth for 10mm asphalt concrete); and at least 2.5 times the dimension of the largest aggregate size in the mix for base and binder courses (i.e. 50mm for 20mm asphalt concrete).
8. CAN I LAY ASPHALT ON TOP OF EXISTING CONCRETE?
This is not recommended. Concrete is a rigid material, whereas asphalt is flexible. When laid on top of concrete, the asphalt cannot ‘flex’, and is therefore more likely to break up. Furthermore, any joints in the concrete will be reflected into the asphalt surface above.
9. HOW LONG DO I NEED TO STAY OFF NEWLY LAID ASPHALT?
This will vary dependant on weather conditions. Normally however, 24 hours without trafficking will be sufficient.
10. WHAT ARE THE DANGERS OF ASPHALT?
The main danger with asphalt is temperature. Asphalt must be laid hot (i.e. above 120°C), which subsequently can result in severe burns. Care must be taken when working with asphalt, and appropriate personal protective equipment (PPE) must be worn at all times.
11. ARE THERE ANY PRECAUTIONS TO BE TAKEN WITH FRESHLY LAID ASPHALT?
Asphalt remains relatively soft for up to one year after laying. When used to construct driveways, it is recommended that cars are moving when the wheels are turned. If a car is stationary when the wheels are turned (particularly with modern power steering), the asphalt can be displaced and scuffed by stresses applied at that particular point. It is also recommended that (wherever possible) vehicles are parked in different positions to avoid marking the asphalt, and fuel spillages are kept to a minimum.
12. WHAT SIZES OF DELIVERY VEHICLES ARE AVAILABLE?
We can supply asphalt in either 16 tonne (‘six wheeler’) or 20 tonne (‘eight wheeler’) loads. Alternatively, customers can collect any size of order above 1 tonne.
13. HOW LONG WILL THE ASPHALT REMAIN HOT?
This will be weather dependant. Provided the asphalt is suitably covered and insulated, asphalt should remain workable for 2 hours after production.
14. WHAT EQUIPMENT WILL I NEED TO LAY ASPHALT?
For hand laying, minimum requirements would be heavy-duty wheel barrows, asphalt rakes, mechanical ‘ride-on’ twin-drum roller, asphalt tamper. For larger projects, specialist machinery will be needed and advice should be sought from paving machinery manufacturers.
15. SHOULD I USE EDGING?
Yes. Unconfined asphalt without edging is more likely to fail than asphalt which has suitable edge protection.
16. HOW CAN I PLACE AN ORDER?
Orders can be taken over the telephone by our Sales Department, by fax, in person at any of our depots, or in writing.
17. HOW CAN I OPEN AN ACCOUNT?
Please contact our Sales Department for information.
