Designated/ Standard Concretes

Standardised Prescribed Concrete:

Standard Mixes:

Standard mixes are a defined list of concretes within BS 8500 which are made with a prescribed quantity of materials as required in the British Standard. These concretes are normally mixed on site on small scale jobs or obtained from a supplier with no quality standards. SPCs are fairly basic mixes and have no strength guarantee, although this can be assumed based on the values contained within BS 8500.

ST1 – Also know as wet lean mix, commonly used for a number of general, non-structural applications including Kerb bedding, drainage works, blinding etc.

Strength – Assume to be 7.5N/mm2 at 28 days

ST2 – An extremely versatile mix used throughout the construction industry for general and housing applications. It is ideal for un-reinforced foundations and bases for houses and extensions.

Strength – Assume 10N/mm2 at 28 days

ST3 –  ST3 is widely used for light duty domestic applications and foundations but not usually suitable as a wearing surface. This would be ideal for Shed bases, foundations for large walls or garages, unreinforced bases etc.

Strength – Assume 15N/mm2 at 28 days.

ST4 – This can be used for many domestic, agricultural and industrial applications and suitable as a wearing surface for light foot traffic

Strength – Assume 20N/mm2 at 28 days.

ST5 – ST5 is used for many domestic, commercial and agricultural applications. Suitable for light foot and trolley traffic only such as agricultural equipment stores, foundations for posts/columns, traffic posts and reinforced ground floor slabs.

Strength – Assume 25N/mm2 at 28 days

General Purpose Concrete:

Gen designation used for a series of concretes that are used for housing, and similar non structural applications. The requirements specify a minimum quantity of cement (minimum cement content, or MCC) to be included, but no water cement ratio (w/c) as such.

GEN0 – GEN0 or wet lean mix concrete is a versatile mix commonly used in both commercial and domestic projects for a wide range of general applications.

Strength – 7.5N/mm2 at 28 days.

GEN1 – GEN1 is an extremely versatile mix used throughout the construction industry for general and housing applications. It is usually used for cavity filling, kerbing, unreinforced domestic foundations in DC-1 soils and haunching.

Strength – 10N/mm2 at 28 days.

GEN2 – GEN 2 provides the ideal material for domestic flooring when no permanent floor finish will be installed but it will be carpeted or tiled.

Strength – 15N/mm2 at 28 days

GEN3 – Gen 3 is commonly used for light duty domestic applications and foundations. It can be used to construct internal floor slabs that contain no embedded metal and will be covered by carpet, tiles or laminate flooring. It is also suitable for domestic garage floors, but we suggest a minimum of RC25/30 should be used if the garage is also used as a workshop.

Strength – 20N/mm2 at 28 days.

Reinforced Concrete:

RC is used for a series of designated concretes that are used in concrete that will be reinforced, pre-stressed or containing embedded steel. The specifications for the RC-series of designated concretes include requirements for maximum w/c ratio (W/C) and minimum cementitious content (MCC), which makes specification easier and complete. The range of uses for this group of mix types ranges in size from a lightly reinforced house or garage floor to industrial and agricultural reinforced concrete that is exposed to highly demanding exposure conditions.

RC20/25 – This type of concrete is suitable for extremely mild exposure conditions for applications such as lightly reinforced house or garage floors which are not designed as suspended and infill to insulated concrete formwork used above ground.

Strength – 25N/mm2 at 28 days.

RC25/30 – This type of concrete is suitable for mild exposure conditions for applications such as lightly reinforced concrete, internal wearing surface for light foot/trolley traffic and reinforced foundations in DC-1 soils.

Strength – 30N/mm2 at 28 days.

RC32/40 – This type of concrete is suitable for moderate to high exposure conditions such as general and agricultural reinforced concrete, livestock and crop store floors, domestic garages used as workshops.

Strength – 35N/mm2 at 28 days.

RC35/40 – This type of concrete is suitable for highly demanding exposure conditions such as agricultural and industrial reinforced concrete, stable floors, floors and walls for silage.

Strength – 45N/mm2 at 28 days.

RC40/50 – RC40/50 is suitable for severe exposure conditions.

Strength – 50N/mm2 at 28 days

Paving Concrete:

These designations give the concrete the necessary level of freeze-thaw resistance for conditions experienced in the UK and are suitable for almost all external domestic and structural roads, pavements and hard standings. These have specified MCC and W/C but also require the mix to contain a minimum air content which varies dependant on the maximum aggregate size used/specified.

PAV1 – This is the most common type of concrete used for domestic pavement construction, where no de-icing salts are used. PAV 1 mixes have an additive that entrains air to create micro sized air bubbles in the concrete. This helps to protect the surface from frost, specifically freeze-thaw cycles, making it especially useful for outdoor paving. Example of PAV1 uses are house driveways, domestic parking/carports, external paving, walkways/patios, hard standings or bases for workshops, houses or extensions. PAV1 is not suitable for powerfloat finishes.

Strength – 35N/mm2 at 28 days.

PAV2 – PAV2 is a substantial, heavy-duty use concrete suitable for commercial and industrial use. PAV 2 mixes have an air entrainment additive to create micro sized air bubbles in the concrete, helping to protect the surface from frost, specifically freeze-thaw cycles, and making it suitable for use with de-icing salts.

Strength – 40N/mm2 at 28 days

Foundation Concrete:

The FND designation used for a series of designated concretes that are used in foundation applications where the ground has been found to contain sulfates. These have specified MCC and W/C and also permit only cement types known to provide appropriate resistance to chemicals found in the ground (primarily sulfates). Foundation concrete for use in sulfate containing soils to DC2-DC4 (design chemical class).

FND2 – (DC-2 Soils)

FND3 – (DC-3 Soils)

FND4 – (DC-4 Soils)

Concrete Strength – 30N/mm2 at 28 days.

Proprietary Concrete:

Proprietary concrete is designed by the concrete producer for a specific purpose or performance requirement. The composition is confidential to the producer and they will offer a performance guarantee for the intended application. Proprietary concrete is used where high performance or specific properties are required such as fast setting, high strength, chemical resistance, low-shrinkage or coloured concretes and self-compacting concretes.

If you have any further questions please don’t hesitate to contact our technical support team to make sure we can design the mix to suit your projects specific needs.