Asphalt & Bitumen Products
Asphalt, also commonly known as tarmac, bitmac, blacktop or macadam is a widely used pavement material used in the construction of roads, footpaths, parking areas and driveways and other specialist applications.
Whether it be collections, small loads, 1000+ tonne supplies or daily deliveries, The Quote Centre can locate the most competitive prices and availability from the very best suppliers.
Tack/bond coats, pitch and crack sealant systems are also available through The Quote Centre.
The suppliers in our community can supply for delivery or collection, day or night to any specification or mix design:
- Asphalt Concrete (AC)
- Dense Macadam
- Open Graded Asphalt
- EME Asphalt
- Hot Rolled Asphalt (HRA)
- Stone Mastic Asphalt (SMA)
- Low Temperature Asphalt
- Porous Asphalt
- Cold Lay Asphalt
- Fine Cold Asphalt
- Proprietary Asphalt
- Sand Carpet
- Tack coat or bond coat
- Overbanding / Pitch
We understand that not everyone is a seasoned asphalt technician and with the many abbreviations mix types just ordering asphalt can be daunting!
We’ve put together a simple guide to asphalt with example uses to help you along the way.
if you're unsure how much to order, use our handy calculator
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In its simplest form asphalt is a mixture of crushed rock, sand and bitumen most commonly mixed at high temperatures of 160 degrees+.
Asphalt may contain additives to improve performance such as polymers, fibres, wax or pigments.
Asphalt is typically black but can be coloured red, blue, green, golden or any other colour required.
Key Elements For Specifying Asphalt
Pavements are typically constructed using a series of layers designed to dissipate the loads and stresses placed upon them.
A capping/sub base material is placed on the formation to provide protection and to support the overlying layers.
The depth and number of layers above the sub base depends on the loads to be placed upon the pavement. A domestic driveway may have only 2 relatively thin layers whereas a motorway may have 3 – 4 layers of a greater thickness.
Asphalt Layers
Base Course
Base Course is the main structural element of a pavement and may be laid in one or more courses based on the loadings to be placed upon the pavement. Basecourse typically utilises a 32mm aggregate. Typically this course will regulate any undulations on the receiving layer (normally a type 1 material)
Binder Course
Binder Course is a load bearing and pavement strengthening layer and is often produced using 20mm aggregate. In public roads and heavy-duty applications it is the intermediate layer between basecourse and surface course.
Surface Course
Surface Course is the top layer that is seen and trafficked and is typically produced using 6mm, 10mm or 14mm aggregate. The selection of the surface course can influence skid resistance, drainage and tyre noise amongst other factors.
The nominal size of an aggregate used within asphalt depends on its application. Typically, the lower in the pavement construction the larger the nominal aggregate size. The most common nominal sizes of aggregate used range from 6mm – 32mm.
The table below highlights the typical nominal sizes used in each pavement layer
Asphalt Layer | Typical Nominal Aggregate Sizes |
Surface Course | 6mm, 10mm, 14mm |
Binder Course | 20mm |
Base Course | 32mm |
Bitumen Penetration grade is typically referred to as ‘Pen’. It is a measurement of the stiffness of the bitumen.
Lower Pen values represent a stiffer bitumen for example a 40/60 pen bitumen is stiffer than a 160/220 pen bitumen.
Bitumen with a lower Pen value has a higher softening point compared to higher pen grades.
The most commonly used bitumen grades in the UK are:
- 40/60
- 70/100
- 100/150
- 160/220
Careful consideration should be given to the softening point of bitumen as the incorrect bitumen selection could result in scuffing or ravelling especially on driveways or car parks. As ambient temperatures rise in the summer months, asphalt can start to soften.
100/150 pen bitumen is the most commonly used bitumen grade however 40/60 is used extensively for heavily trafficked roads. 160/200 is often used for hand lay work as it is easier to apply.
Polymer Modified Bitumen (PMB) is a bitumen with polymers added to provide higher performance. They are often used in high traffic or high stress areas as they provide greater rigidity and resistance to deformation, amongst other benefits.
Fibres are added to some asphalt mixes to improve the strength and durability of the pavement and allow an increased bitumen content.
The Polished Stone Value of aggregate gives a measure of resistance to the polishing action of vehicle tyres and is used in surface course applications.
The state of polishing is one of the main factors affecting the pavements skid resistance. This is not normally a concern for private roadways or drives but is a major consideration of designers of high speed, high traffic pavements.
High PSV aggregate is limited in availability and careful consideration to its specification should be undertaken. This is a premium aggregate and can come with a premium cost.
PSV value typical range from 50 – 68+ with the high value offering the greatest resistance to polishing.
Asphalt Mix Types
There are many different asphalt mixes that can incorporate differing penetration grade bitumens, aggregate sizes and PSV aggregates. Below is a summary of the most common mix families:
Asphalt Concrete (AC) mixes are the most commonly used asphalt in the UK. They are available in a variety of aggregate gradings / sizes that alter the characteristics of the material. The options are listed below:
- Dense
- Open
- Medium
- Close
As an example, a close graded material achieves its strength by the aggregate interlock of the close aggregate grading. On the other hand, an open graded material trades strength properties with more of gap graded aggregates which can assist in water shed and surface texture.
Hot Rolled Asphalt (HRA) is predominately used on high speed or major roads. HRA is a gap graded material which uses a stiff binder with a large amount of fine aggregate (Predominately sand) to provide a durable weather resistant mastic surfacing.
To achieve a good surface texture, pre coated high PSV chippings (PCC) may be rolled into the material before cooling.
The PCC also vary in size and PSV and overspreading should be avoided. 1t of PCC is normally sufficient for 10t of HRA to provide a low to medium surface texture.
Consideration should be given to a wastage factor when ordering PCC. HRA & PCC is normally laid with experienced asphalt crews as the embedment of the PCC is critical. Normally only specialist plants produce PCC and they may come from a different plant when ordering in conjunction with HRA.
Stone Mastic Asphalt (SMA) is a gap graded material which obtains its strength and rutting resistance from the high binder content and usually has the addition of fibres to stop the binder from draining or ‘fatting up’.
SMA is often specified in place of HRA due to the reduced tyre noise and ease of laying. Care should be taken when hand laying as the mix can cool quickly due to the lack of fines, hand lay areas will look visually more open than a machine laid area.
EME is used as a base or binder and is manufactured using a very low penetration binder. They have a high stiffness and fatigue resistance, ideal for use in high stress environments and are typically used on highly trafficked trunk roads and motorways.
Porous Asphalt is commonly used in Sustainable Urban Drainage Systems (SUDS) or integrated into a drainage system
They are permeable and can mitigate water run off that could overwhelm surface water drainage systems in flash flood events.
Consideration must be given to an aftercare plan when laying porous asphalt as they require regular cleaning to retain the porosity of the finished surface. Depending on the design criteria porous asphalt should be laid as a complete system, with the base, binder and type 1 also having porous properties.
Low Temperature Asphalts are asphalts produced and laid at a lower temperature to conventional asphalts, (typically 30 degrees c lower) offering increased sustainability.
The lower mixing temperature is achieved through the use of additives, with most mixes (with the exception of HRA) available as a low temperature asphalt.
Low temperature asphalt is not as readily available as conventional hot asphalt, although it is becoming more common due to the environmental and health and safety benefits it offers.
Cold Asphalts utilise an emulsified bitumen (Bitumen mixed with water) or a foamed bitumen (Bitumen injected with water and air).
The mixes often incorporate high percentages of recycled asphalt into the mixes, improving their sustainability. Cold asphalt can also be produced to have a shelf life which offers operational advantages.
They are typically used in base and binder applications, however, surface courses are possible. As with low temperature asphalts they are not as readily available as hot asphalts but they do have the advantage of the ability to be site batched. Offering larger projects an on-site production facility that can reduce costs and environmental impacts significantly.
This should not be confused with Cold Asphalt although it is produced hot and allowed to cool.
This is commonly known as FCA, ramping, cut back or deferred set and is usually used for ramping, making safe and emergency repairs.
There are varying ways of manufacturing FCA, including additives, which allow the material to remain workable for up to 28 days.
This material is used as a temporary fix or safety measure and should not normally be overlaid or incorporated into permanent works. This can also be supplied in bags but not all asphalt plants can produce this.
Proprietary Asphalts are usually variations on AC, HRA & SMA mixes.
They are performance designed mixes which have been modified to enhance a certain property or properties.
For example, more rut resistant, higher softening point or specified texture depth level.
Many producers offer propriety mixes for specific applications,
The Quote Centre can provide options from the leading suppliers to suit your needs.
Tack and Bond Coats
Tack and Bond Coats are a water and bitumen mix that is spray applied and improve the bond between the layers of pavement
A tack or bond coat also provides additional waterproofing to the pavement structure.
Tack coats are usually applied cold and bond coats applied hot by sprayer
There are many different types of tack coats and bond coats with different percentages of bitumen within the product. Bond coats can contain polymer modified bitumen to improve their performance
Asphalt Rate Of Spread Table
Average Thickness | AC Medium and Open graded Surface and Binder Courses |
AC Dense Surface, Base and Binder courses |
HRA Surface, Base and Binder courses |
SMA Surface and Binder Courses |
EME2 Binder Course |
mm | m2/tonne | m2/tonne | m2/tonne | m2/tonne | m2/tonne |
15 |
| 24 – 30 |
|
|
|
20 |
| 18 – 22 |
| 18 – 23 |
|
25 |
| 14 – 18 | 15 – 19 | 15 – 18 |
|
30 | 13 – 16 | 12 – 15 | 12 – 16 | 12 – 14 |
|
35 | 11 – 14 | 10 – 13 | 10 – 14 | 10 – 13 |
|
40 | 10 – 12 | 9 – 11 | 9 – 12 | 9 – 11 |
|
45 | 9 – 11 | 8 – 10 | 8 – 11 | 8 – 10 |
|
50 | 8 – 10 | 7 – 9 | 7 – 9 | 7 – 9 |
|
60 | 7 – 8 | 6 – 7 | 6 – 8 | 6 – 8 | 6 – 7 |
70 | 6 – 7 | 5 – 6 | 5 – 7 | 5 – 6 | 5 – 6 |
80 |
| 4 – 6 | 5 – 6 | 5 – 6 | 5 – 6 |
90 |
| 4 – 5 | 4 – 5 | 4 – 5 | 4 – 5 |
100 |
| 4 – 4 | 4 – 5 |
| 4 – 4 |
110 |
| 3 – 4 | 3 – 4 |
| 3 – 4 |
120 |
| 3 – 4 | 3 – 4 |
| 3 – 4 |
130 |
| 3 – 3 | 3 – 4 |
| 3 – 3 |
140 |
| 3 – 3 | 3 – 3 |
| 3 – 3 |
150 |
| 2 – 3 | 2 – 3 |
| 2 – 3 |
Use Guidance Tables
The tables below provide information on common asphalt uses and the typical mixes used.
| Pedestrian and light vehicle usage | Heavy Vehicle Usage | ||||
Construction Layer | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) |
Surface Course | SMA 6 surf | 100/150, 70/100*or 40/60 | 25 | SMA 6 surf | 100/150, 70/100 or 40/60* | 25 |
SMA 10 surf | 100/150, 70/100* or 40/60 | 25 | SMA 10 Surf | 100/150, 70/100 or 40/60* | 25 | |
AC 4 fine surf | 160/220 or 100/150* | 25 | AC 4 Fine Surf | 160/220 or 100/150* | 25 | |
AC 6 dense surf | 160/220 or 100/150* | 25 | AC 6 dense Surf | 160/220 or 100/150* | 25 | |
AC 14 close surf | 160/220, 100/150 or 70/100* | 40 | AC 14 close surf | 160/220, 100/150 or 70/100* | 40 | |
AC 6 med surf | 160/220 or 100/150* | 25 | AC 6 med Surf | 160/220 or 100/150* | 25 | |
HRA 50/10 F surf | 100/150, 70/100* or 40/60 | 40 | HRA 50/10 F surf | 100/150, 70/100 or 40/60* | 40 | |
Proprietary Products | Manufacturers Specification | Manufactures Recommendation | Proprietary Products | Manufacturers Specification | Manufactures Recommendation | |
Binder Course | AC 20 dense bin | 100/150*, 70/100 or 40/60 | 50 | AC 20 dense bin | 100/150* or 40/60 | 90 |
HRA 50/14 bin | 100/150, 70/100* or 40/60 | 50 | HRA 50/14 bin | 100/150, 70/100 or 40/60 | 90 | |
Base Course | Type 1 Sub Base | N/A | 100 – 225 | Type 1 Sub Base | N/A | >250 |
Type 2 Sub Base | N/A | 100 – 225 | Type 2 Sub Base | N/A | >250 | |
Type 4 Sub Base | N/A | 100 – 225 | Type 4 Sub Base | N/A | >250 | |
| Light usage | Heavier Usage | ||||
Construction Layer | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) |
Surface Course | SMA 6 surf | 100/150, 70/100 or 40/60* | 25 | HRA 30/14 surf | 40/60 | 40 |
AC 6 med surf | 160/220 or 100/150* | 25 | AC 10 Close Surf | 100/150, 70/100 or 40/60* | 30 | |
AC 6 dense surf | 160/220 or 100/150* | 25 | SMA 10 surf | 40/60 or PMB | 30 | |
AC 10 close surf | 160/220 or 100/150* | 30 | SMA 6 surf | 40/60 or PMB | 30 | |
Proprietary Products | Manufacturers Specification | Manufactures Recommendation | Proprietary Products | Manufacturers Specification | Manufactures Recommendation | |
Binder Course | AC 20 dense bin | 100/150* or 40/60 | 60 | HRA 60/20 bin | 40/60* | 60 |
AC 20 open bin | 100/150* or 160/220 | 60 | AC 20 dense bin | 100/150 or 40/60* | 60 | |
Base Course | Type 1 Sub Base | N/A | 150 | Type 1 Sub Base | N/A | 200 |
AC32 dense bin | 100/150* or 40/60 | 75 | AC32 dense bin | 100/150 or 40/60* | 100 | |
| Medium Vehicles | Heavy Vehicles | ||||
Construction Layer | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) |
Surface Course | HRA 30/14 surf | 40/60 | 40 | HRA 55/10 surf | 40/60 or PMB | 40 |
SMA 10 surf | 100/150, 70/100 or 40/60* | 30 | SMA 10 surf | 40/60* or PMB | 30 | |
Proprietary Products | Manufacturers Specification | Manufactures Recommendation | Proprietary Products | Manufacturers Specification | Manufactures Recommendation | |
Binder Course | AC 20 dense bin | 100/150 or 40/60* | 60 | AC 20 dense bin | 100/150 or 40/60* | 60 |
HRA 60/20 bin | 40/60* | 60 | HRA 60/20 bin | 40/60* | 60 | |
Base Course | AC32 dense base | 100/150 or 40/60* | 100 | AC32 dense bin | 100/150 or 40/60* | 150 |
HRA 60/32 base | 40/60* | 100 | HRA 60/32 base | 40/60* | 125 | |
| Impermeable Construction | Permeable Construction | ||||
Construction Layer | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) |
Surface Course | HRA 30/6 F surf | 40/60* | 30 | PA 6 surf | 160/220 or 100/150* | 25 |
HRA 0/2 F surf | 40/60* | 25 | AC 6 open surf | 160/220 or 100/150* | 25 | |
AC 4 fine surf | 160/220,100/150* or 70/100 | 20 | AC 6 med surf | 160/220 or 100/150* | 25 | |
AC 6 dense surf | 160/220, 100/150* or 70/100 | 25 | Proprietary Products | Manufacturers Specification | Manufactures Recommendation | |
Binder Course | AC 20 dense bin | 100/150* | 50 | AC 20 open bin | 160/220 or 100/150* | 50 |
HRA 60/20 bin | 40/60* | 45 | AC 14 open bin | 160/220 or 100/150* | 45 | |
PA 20 bin | 40/60, 70/100 or100/150* | 50 | ||||
PA 14 bin | 40/60, 70/100 or100/150* | 45 | ||||
Base Course | AC32 dense bin | 100/150* or 40/60 | 75 | PA 20 bin | 40/60, 70/100 or100/150* | 80 |
HRA 60/32 | 40/60* | 75 | PA 14 bin | 40/60, 70/100 or100/150* | 60 | |
Type 1 Sub Base | N/A | 100 – 150 | Type 3 or Type 1 x sub base | N/A | 150 | |
| Light – Medium Vehicles | Heavy Vehicles | ||||
Construction Layer | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) |
Surface Course | HRA 45/6 surf | 40/60* | 30 | HRA 45/6 surf | 40/60* or PMB | 35 |
HRA 45/10 | 40/60 | 40 | HRA 45/10 surf | 40/60* or PMB | 45 | |
Surface Dressing | Emulsion Site Specific | Site Specific | Proprietary Products | Manufacturers Specification | Manufactures Recommendation | |
Proprietary Products | Manufacturers Specification | Manufactures Recommendation | ||||
Binder Course | AC 20 Dense bin | 100/150, 70/100, 40/60* | 60 | AC 20 Dense bin | 100/150, 70/100, 40/60* | 80 |
HRA 60/20 | 40/60* | 50 | AC HDM 20 Dense bin | 40/60* | 80 | |
HRA 60/20 bin | 40/60* | 60 | ||||
Base Course | AC32 dense bin | 100/150, 70/100 or 40/60* | 75 | AC32 dense bin | 100/150, 70/100 or 40/60* | 100 |
HRA 60/32 | 40/60* | 75 | AC32 HDM dense bin | or 40/60* | 100 | |
Type 1 Sub Base | N/A | 200 – 400 | HRA 60/32 | 40/60* | 100 | |
| Light – Medium Vehicles | Heavy Vehicles | ||||
Construction Layer | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) | Materials | Binder Grade (*=preferred) | Nominal Layer Thickness (mm) |
Surface Course | HRA 45/6 surf | 40/60* | 30 | HRA 45/6 surf | 40/60* or PMB | 35 |
HRA 45/10 | 40/60 | 40 | HRA 45/10 surf | 40/60* or PMB | 45 | |
Proprietary Products | Manufacturers Specification | Manufactures Recommendation | Proprietary Products | Manufacturers Specification | Manufactures Recommendation | |
Binder Course | AC 20 Dense bin | 100/150, 70/100, 40/60* | 60 | AC 20 Dense bin | 100/150, 70/100, 40/60* | 80 |
HRA 60/20 | 40/60* | 50 | AC HDM 20 Dense bin | 40/60* | 80 | |
HRA 60/20 bin | 40/60* | 80 | ||||
Base Course | AC32 dense bin | 100/150, 70/100 or 40/60* | 75 | AC32 dense bin | 100/150, 70/100 or 40/60* | 100 |
HRA 60/32 | 40/60* | 75 | AC32 HDM dense bin | or 40/60* | 100 | |
Type 1 Sub Base | N/A | 200 – 400 | HRA 60/32 | 40/60* | 100 | |
Notes
- The materials listed as suitable may not be considered best practice, site conditions and usage need to be taken into account in material selection
- Where subbases are listed in place of base courses, a bituminous base course is not considered necessary
- The information above is for information and guidance purposes only. The Quote Centre cannot accept liability for design or material selection
- All asphalt relies on compaction and insufficient consolidation will result in premature failure not matter how durable the specified mix is. Careful selection of compaction machinery and the determination of rolling patterns is the key to success, bear in mind that over compaction can be as damaging as under compaction.
- Health and Safety – Most asphalt is produced hot and care should be taken when applying, suitable PPE should be worn at all times.
For further guidance, the Mineral Products Association has some excellent documents that can be found here
Guidance on Highway Pavement Design can be found in the Standards for Highways, Design Manual for Roads and Bridges here