Concrete strength classes

M20 nominal concrete

A workhorse structural nominal mix. Widely used for driveways, strip footings and lightly reinforced domestic slabs. Highest nominal mix commonly batched by volume.

Mix ratio

1 : 1.5 : 3

Cement : Sand : Aggregate

Proportions & strength

Designation	M20
Ratio (by volume)	1 : 1.5 : 3
Cement	1 part
Sand	1.5 parts
Aggregate	3 parts
Typical compressive strength	2,900 psi · 20 MPa
Typical use	Driveways, footings, reinforced slabs (light).

Planning reference. Strengths are typical values for a well-made mix at 28 days, not a guaranteed design strength. Structural work must follow your local building code and a qualified engineer's mix design.

Where M20 is used

A workhorse structural nominal mix. Widely used for driveways, strip footings and lightly reinforced domestic slabs. Highest nominal mix commonly batched by volume.

Nominal mixes like this are proportioned by volume on site and suit general and domestic work. Anything structural — reinforced, load-bearing or engineered — should use a design mix proportioned by weight from tested materials.

Need quantities? The volume calculators give the cubic yards, cubic metres and bag counts for the pour this mix goes into.

Applications

Jobs that use M20

Concrete mix for a drivewayConcrete mix Concrete mix for a footingConcrete mix Concrete mix for a garage floorConcrete mix Concrete mix for a slabConcrete mix Concrete mix for stepsConcrete mix

Same family

Other concrete strength classes

M51 : 5 : 10Blinding / levelling course under footings.M7.51 : 4 : 8Blinding, mass fill, non-structural pads.M101 : 3 : 6Levelling courses, path bedding, kerb backing.M151 : 2 : 4Paths, patios, shed and light slab bases.M251 : 1 : 2Reinforced footings, columns, structural slabs.M30Design mixStructural columns, beams, suspended slabs.