Types of concrete
Concrete broadly falls into four categories: standard prescribed concrete (SPC), designated concrete, designed concrete and proprietary concrete. There are different types of concrete grades:
General concrete: GEN0 | GEN1 | GEN2 | GEN3
Reinforced concrete: RC20/25 | RC25/30 | RC28/35 | RC32/40 | RC35/45 | RC40/50
Foundation concrete: FND2 | FND3 | FND4
Standardised prescribed concrete: ST1 | ST2 | ST3 | ST4 | ST5
Designated concretes
Designated concretes have been developed to make the selection of appropriate concrete simpler and more reliable. While they do not cover every application and they restrict or limit the use of certain materials, they are suitable for many housing, agricultural and structural applications.
An essential part of the designated concrete concept is the requirement for the producer to hold an appropriate level of product conformity certification, this requirement has been approved by the BSI Standards Policy and Strategy Committee. It is recognised that in many construction works the user might not have expertise in concrete design or specification, being able to select a product based on its application rather than specifying specific limiting values makes correct selection much easier. Simplifying the ordering process reduces the chance of error and increase the likelihood of achieving the required durability and design life.
It is the user/designers choice as to whether designated concrete is specified, and having elected to specify a designated concrete then all its requirements, including those for third-party product conformity certification, are expected to be met.
Designated concrete’s are grouped by name in to General (GEN), Reinforced (RC), Foundation (FND) and Pavement (PAV) each suitable for a range of applications within each series.
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, they have relatively low levels of durability.
GEN0
GEN 0 or wet lean mix concrete is a versatile mix commonly used in both commercial and domestic projects for a wide range of general applications, non-structural applications.
Applications:
Concrete strength: 7.5N/mm2 at 28 days
GEN0 should not be used externally unless completely covered or encased.
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.
Applications:
- un-reinforced strip footings
- trench-fill foundations
- some agricultural applications
- foundations for walls, sheds and conservatories
- drainage works
- blinding house floors
- pad foundations
- non-structural mass concrete in non-aggressive (DC-1) ground conditions
- cavity fill
- mass fill
- kerbing
- haunching
Concrete strength: 10N/mm2 at 28 days
GEN1 should not be used externally unless completely covered or encased.
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.
Applications:
- un-reinforced strip footings
- trench-fill foundations
- foundations for walls, sheds and conservatories
- paving for steps and paths
- blinding
- un-reinforced mass concrete fill
- strip footings
Concrete strength: 15N/mm2 at 28 days
GEN2 should not be used externally unless completely covered or encased.
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.
Applications:
- Driveway, shed and workshop bases
- foundations for walls, garages, houses and extensions
- under paving for patios
- un-reinforced bases and oversites for conservatories, garages, sheds, greenhouses
- domestic garage floors with no embedded metal
- Blinding
- mass concrete fill
- un-reinforced strip footings
- trench-fill foundations
Concrete strength: 20N/mm2 at 28 days
GEN3 should not be used externally unless completely covered or encased.
Have a query? Please contact customer service for more information at the contact numbers listed on this page.
Reinforced Concrete (RC)
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
- lightly reinforced house or garage floors, not designed as suspended
- infill to insulated concrete formwork used above ground
Concrete strength: 25N/mm2 at 28 days
RC25/30
This type of concrete is suitable for mild exposure conditions.
Applications:
- lightly reinforced concrete
- internal wearing surface for light foot and trolley traffic
- reinforced foundations in DC-1 soils
Concrete strength: 30N/mm2 at 28 days
RC28/35
This is for moderate exposure conditions.
Applications:
- general and agricultural reinforced concrete
- livestock and crop store floors
- domestic garages used as workshops
Concrete strength: 35N/mm2 at 28 days
RC32/40
RC32/40 is suitable for moderate to high exposure conditions.
Applications:
- general, agricultural and industrial reinforced concrete
- floors and walls for manure and slurry stores or mushroom sheds
- general industrial floors subjected to small-wheeled forklift trucks
Concrete strength: 40N/mm2 at 28 days
RC35/45
This type of concrete is suitable for for highly demanding exposure conditions
Applications:
- agricultural and industrial reinforced concrete
- stable floors
- floors and walls for silage or brewer’s grain stores
- floors for parlours and dairies
Concrete strength: 45N/mm2 at 28 days
RC40/50
RC40/50 is suitable for severe exposure conditions.
Applications:
- agricultural and industrial reinforced concrete
- stable floors
- floors and walls for silage or brewer’s grain stores
- floors for parlours and dairies
Concrete strength: 50N/mm2 at 28 days
Have a query? Please contact customer service for more information at the numbers listed on this page.
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.
Applications:
- house driveways
- domestic parking/car ports
- external paving
- domestic, agricultural and industrial paved areas such as walkways and patios
- reinforced and un-reinforced hard standings
- reinforced and un-reinforced bases for workshops, houses and extensions
Concrete strength: 35N/mm2 at 28 daysNote:
This is not suitable for powerfloat finishes
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.
Applications:
- external slabbing and paving subject to industrial vehicles and machinery
- reinforced bases for commercial buildings and agricultural storage areas
Concrete strength: 40N/mm2 at 28 days
Note: This is not suitable for powerfloat finishes.
Have a query? Please contact customer service for more information at the numbers listed on this page.
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)
All types of unreinforced foundations
Concrete strength: 30N/mm2 at 28 days
FND3 – (DC-3 Soils)
All types of unreinforced foundations
Concrete strength: 30N/mm2 at 28 days
FND4 – (DC-4 Soils)
All types of unreinforced foundations
Concrete strength: 30N/mm2 at 28 days
Have a query? Please contact customer service for more information at the numbers listed on this page.
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. View our ready-mixed concrete range to see the different proprietary concrete types and uses we have available.
Have a query? If you are still unsure of what type of concrete suits your project or would like more information please contact customer service at the numbers listed on this page.
Standardised prescribed concrete
*Standardised concrete should not be used, suppliers holding third party quality accreditation to ISO 9001 are able to offer designated concrete as a lower carbon, quality assured alternative
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. See the following for concrete mixes and their uses in this category:
ST1
ST1 or wet lean mix concrete: commonly used in both commercial and domestic projects for a wide range of general, non-structural applications.
Applications:
Blinding is the process of pouring a thin layer of concrete over the floor of a new building; this can be over the hardcore or over the foundation itself. The purpose of this is to seal in underlying material and prevent dirt and mud from interfering with the structure.
Strength: Assume to be 7.5N/mm2 at 28 days
If supplies are from a quality assured supplier use GEN0
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, trench-fill, kerbing, patios and unreinforced house floors as long as a permanent finish (such as a screed or floating floor) will be added.
Applications:
- un-reinforced strip footings
- trench-fill foundations
- some agricultural applications
- drainage works
- blinding house floors
- pad foundations
- non-structural mass concrete in non-aggressive (DC-1) ground conditions
- footings for fence posts
- infilling around manholes
- small bases for external furniture, such as patios
- mass concrete fill
Strength: Assume 10N/mm2 at 28 days
If supplies are from a quality assured supplier use GEN1.
ST3
ST3 is widely used for light duty domestic applications and foundations but not usually suitable as a wearing surface. It can be used to construct internal floor slabs providing they don’t contain embedded metal and is ideal for house floors with no permanent finish (e.g. carpet or laminate) flooring.
Applications:
- shed and workshop bases
- foundations for large walls, garages, houses and extensions
- paving for patios
- unreinforced bases and oversites for conservatories, garages, sheds and greenhouses
Strength: Assume 15N/mm2 at 28 days
If supplies are from a quality assured supplier use GEN2.
ST4
ST4 is used for many domestic, agricultural and industrial applications and suitable as a wearing surface for light foot traffic.
Applications:
- garage floors (not designed as suspended and not reinforced)
- shed and workshop bases
- internal floor slabs (containing no embedded metal)
- drain/channel bedding
- benching to chambers
Strength: Assume 20N/mm2 at 28 days
If supplies are from a quality assured supplier use GEN3.
ST5
ST5 is used for many domestic, commercial and agricultural applications. Suitable for light foot and trolley traffic only.
Applications:
- agricultural equipment stores
- foundations for environmental barrier posts and planted lighting columns
- foundations for traffic sign posts
- house and garage ground floor slabs fully or nominally reinforced, either ground bearing, suspended or over sub-floor voids
Strength: Assume 25N/mm2 at 28 days if supplies are from a quality assured supplier use an RC20/25.
Have a query? Please contact customer service for more information at the contact details listed on this page.
