Sub-Base Aggregates

The Highway Agency's Specification for Highway Works, Clause 803 (SHW 803). Also known as GSB TYPE 1 or MOT TYPE 1 - this is a granular material with a maximum permitted top size of 63mm, graded down to dust.

Type 1 must be of a crushed nature to provide a stable sub-base for road surfaces and pathways. The mixture of solids and fines ensures minimal voids in the sub-base material when compacted, giving a strong load bearing layer with a suitably flat surface.

Typical use is as a finished surface prior to a top coating of asphalt, concrete, shingle and block paving. Should be non-frost susceptible when used within 450mm of the finished surface and is generally a 40mm, evenly graded, hard material. Both primary and recycled constituents can be used to produce a Type 1 sub-base.

Please Note -Type 1 has a lower fines percentage than scalpings and therefore a greater load bearing capability. It is the recommended material for highly trafficked areas such as highways, car parks, footpaths, driveways and hard standings.

Type 1: Primary Limestone

Held in stock at most of our rail connected depots.

Type 1: Primary Granite

Specialist Type 1 material available across the South East and nationally.

Type 1 Recycled Aggregate

Crushed, screened materials produced in house by our state of the art recycling plants, situated across London and the South East. Available nationally.

Type 1: EcoBlend™

A mixture of primary and recycled aggregate, combining the advantages of both. Click here to see more on our EcoBlend™ products (pdf)

Type 1: Recycled Black and White

A competitively priced mix of crushed concrete and crushed asphalt.

Limestone Scalpings

Fill or sub-base material used in the construction of access paths, car parks, driveways, backfill to structures, or other light-use applications where a suitable, lower cost alternative to Type 1 is required. Grading for this material is generally 40mm to dust with some clay, and it is classed as non-frost susceptible.

Please note: Scalpings have a higher percentage of fines than Type 1 and therefore have less load bearing capability.

Type 3 Limestone

40mm unbound mixture used for sub-base applications as per the Specification for Highway Works, Clause 803. Generally open graded with a reduced amount of fines (not zero fines) which improves drainage when compared with Type 1. Widely used for sports pitches, equestrian arenas, driveways and tennis courts where drain blockage may be an issue and where SUDS (Sustainable Urban Drainage Systems) legislation is imposed. Also used as a sub-base material in hard standings, haul roads, paths and patios.

20/40 Limestone

Crushed limestone with low fines content that forms a hard wearing and well drained surface when compacted. Can be used as a free draining sub-base in equestrian riding arenas, roads, paths and drainage ditches.

40/75 Limestone

As above and often used in conjunction with 20/50mm Limestone as a lower layer.

Other Dry Screened Limestone Sizes available

• 10/63mm graded
• 32/50mm graded
• 20/32mm single sized
• 10/20mm single sized
• 6/14mm single sized
• 4/10mm single sized
• 2/6mm single sized
• 4/20mm graded limestone

Washed Limestones

These are washed to remove fines and often referred to as cleanstones.

• 20/40mm single sized
• 4/20mm graded limestone

Granites

Day Group also supplies a range of granite aggregates in the following size ranges:

• 4/20mm
• 10/20mm
• 20/32mm
• 20/40mm
• 28/50mm (Track Ballast)

Sub-Bases Using Recycled Aggregates

Day Group specialises in supplying sub-bases using sustainable recycled materials.

Type 2: Recycled

An unbound sub-base material with more fines and a wider grading envelope than Type 1. Normally used as a layer under Type 1.

6F5 Recycled (Formerly 6F2 Recycled)

Typically used for capping sub formations prior to laying Type 1 or Type 2 sub-base. Well graded material ranging from 125mm to dust.

6F4 Recycled (Formerly 6F1 Recycled)

Finer Capping Layer used in the same applications as 6F5 but with a finer grading. Generally 50mm to dust and evenly graded.

Type 3 Recycled (formerly Type1x Recycled)

40mm unbound mixture utilising recycled aggregate. Used for sub- base applications as per the Specification for Highway Works, clause 803. Generally open graded with a reduced amount of fines (not zero fines) to improve drainage in comparison to Type 1. Widely used for sports pitches, equestrian arenas, driveways and tennis courts where drain blockage may be an issue, particularly where SUDS (Sustainable Urban Drainage Systems) legislation is imposed. Also used as a sub-base material in hard standings, haul roads, paths and patios.

6N and 6P Recycled

Selected granular fills for use in embankments and as backfill to concrete structures. 100% passing a 75mm sieve with no more than 15% passing 63 microns.

Road Planings

Waste product of road resurfacing, used for hard standing and ideal as a finished surface for building sub-bases and farm tracks. Not suitable for drainage trenches.

Crushed Asphalt

A crushed recycled material with good cohesive qualities, often used as a hard core for temporary roadways and as a sub-base. Normally supplied as a 0-50mm and often referred to as a Type 4.