Concrete Selection

General Mixes (GEN)	General mixes (GEN) are produced to British and European standards to guarantee high quality. Each has a designed strength and minimum cement content. They are most commonly used in foundations or domestic flooring.
Reinforced Mixes (RC)	Most commonly used where steel reinforcement is present. The characteristics of each mix is specified by British and European standards to produce strength and durability qualities. These help to reduce the risks of the steel being attacked by aggressive chemicals.
Standard Mixes (ST)	These have a broad range of uses, and while there is no guaranteed designed strength, a minimum cement content is specified in British and European standards. The mixes range from ST1 to ST5 and their uses range from kerb backing to concrete slabs.
Designed Mixes (C)	Usually specified by the engineer, architect or designer, they are manufactured to achieve a particular strength. Other properties may also be specified. These details would usually be found on the construction drawings, specification or bill of quantities.

 

Application	Designated Concrete	Recommended Consistence Class
Unreinforced foundations and associated works
Blinding and mass concrete fill	GEN1	S3
Strip footings	GEN1	S3
Mass concrete foundations	GEN1	S3
Trench fill foundations	GEN1	S4
Drainage works to give immediate support	GEN1	S1
Other drainage works	GEN1	S3
Oversite below suspended slab	GEN1	S3
Unreinforced foundations requiring DC-2 to DC-4 concrete
DC-2	FND2	S3
DC-2z	FND2Z	S3
DC-3	FND3	S3
DC-3z	FND3Z	S3
DC-4	FND4	S3
DC-4z	FND4Z	S3
DC-4m	FND4M	S3
General applications
Kerb bedding & backing	GEN0	S1
Floors
House floors with no embedded metal
- Permanent finish added e.g a screed or floating floor	GEN1	S2
- No permanent finish to be added e.g carpeted	GEN2	S2
Garage floors with no embedded metal	GEN3	S2
Wearing surface: Light foot and trolley traffic	RC25/30	S2
Wearing surface: general industrial	RC32/40	S2

The selection of fresh concrete should be suitable for the conditions of handling and placing so that after compaction, concrete surrounds all reinforcement, tendons and ducts and completely fills the formwork. The table below gives guidance on the consistence expressed as slump [S (number)] classes appropriate to different uses. Where a concrete is to be laid on a slope, a lower slump class than that given in table below might be necessary.

Use of Concrete	Form of Compaction	Consistence Class
Consistence suitable for different uses of in-situ concrete
Kerb bedding and backing	Tamping	S1
Floors and hand placed pavements	Poker or beam vibration	S2
Strip footings	Poker or beam vibration	S3
Mass concrete	Poker or beam vibration	S3
Foundations	Poker or beam vibration	S3
Blinding	Poker or beam vibration	S3
Normal reinforced concrete in slabs,	Poker or beam vibration	S3
beams, walls and columns	and/or tamping

You can calculate your concrete requirements by multiplying the length x breadth x depth of the area or areas which the concrete is needed to fill.

Be sure to make allowances for areas which may be slightly wider or deeper. We can supply and deliver concrete with a minimum quantity of 0.5 cubic metres up to 7 metres in one truck load.

As an estimate, one cubic metre is approximately 20 to 25 wheelbarrow loads.