STRENGTH GUIDE FROM PALMIX 

STRENGTH GUIDE FROM PALMIX 

Our concrete strength guide will help you choose the right mix for your project requirements. 
 
Concrete is a strong and long-lasting composite material made from cement, water, coarse and fine aggregates and often an admixture. 
 
When first poured, concrete gains strength quickly and then the process slows down. After 28 days it will normally achieve between 90% and 99% of its overall strength. As a result, concrete strength is based on industry-standard compression tests carried out after 28 days. 
 
You can choose different concrete mixes and additives to suit your needs. Here’s a general guide to different concrete strengths and uses. 
 
Please note: You should always refer to drawings, technical specifications and professional recommendations before placing your order. 

CONCRETE STRENGTHS OUR GUIDE 

CONCRETE STRENGTHS OUR GUIDE 

C10

C10 

For firm bases that don’t need structural strength. 
Uses: Drainage works, floor blinding, foundations for steps, filling voids. 
C15

C15 

Suitable for house floors without embedded metal. 
Uses: Internal floors with non-permanent finishes such as carpet and lightweight kerb bedding. 
C20

C20 

Lightweight and domestic use. 
Uses: Fence posts, patio paving, greenhouses and kerbing. 
C25

C25 

Lightweight commercial and domestic use often with reinforcement. 
Uses: Hot tub and shed bases, foundations and reinforced bases, infilling around manholes and kerbing. 
C30

C30 

External paving and floor slabs. 
Uses: Reinforced hard standings and bases, house foundations. 
C35

C35 

A wide range of domestic and commercial uses. 
Uses: Reinforced foundations for houses and retaining walls, agricultural storage areas, driveways and garage floors. 
C40

C40 

Commercial uses requiring high structural strength and support. 
Uses: Standings for HGVs, agricultural yards, septic tank foundations, structural beams. 
C45 / C50

C45 & C50  

Specialised projects requiring strength and support. 
Uses: Heavy industrial applications. 

C10 CONCRETE CONCRETE STRENGTH GUIDE 

C10 CONCRETE CONCRETE STRENGTH GUIDE 

C10 / GEN 1 concrete is perfect for lightweight projects such as shed footings , drainage and cavity fill. This mainly non-structural concrete mix is widely used across the construction industry for general purpose domestic applications. It should never be used outside unless entirely covered or encased. 
 
Uses: 
Pads, non-load bearing wall or shed foundations 
Unreinforced domestic foundations built in DC-1 soils 
Blinding & oversite below suspended floors 
Some drainage work up to 10 Newtons 
Trench and Cavity fill 
Kerbs and haunching 
Unreinforced strip footings 
 
Strength: 
10Nm after 28 days 

C15 CONCRETE CONCRETE STRENGTH GUIDE 

C15 CONCRETE CONCRETE STRENGTH GUIDE 

C15 / GEN 2 concrete is suitable for house floors that have no embedded metal reinforcement and is suitable for house and internal floors where the floor is to be covered by carpet/tile or other types of covering. It can be used for both commercial and domestic projects and can be used outside, but must be encased or fully covered. 
 
Uses: 
Floors with no embedded metal 
Unreinforced and reinforced strip footings for small walls 
Trench fill 
Wall and shed foundations 
Steps and path paving 
Blinding 
Mass unreinforced fill 
 
Strength: 
15Nm after 28 days 

C20 CONCRETE CONCRETE STRENGTH GUIDE 

C20 CONCRETE CONCRETE STRENGTH GUIDE 

C20 / GEN 3 / ST1 concrete is versatile and easy to work with and is most commonly used for light weight and domestic and commercial applications. Sometimes used for internal floor slabs that contain no embedded metal, but which need to be covered. 
 
Uses: 
Single story foundations 
Internal floor slabs which don’t contain metal and will be covered over 
Domestic garage floors but if its intended to use the garage as a work shop then C35/ST4 is recommended 
Base for driveways and patios 
Blinding 
Trench Fill 
Unreinforced strip footings 
Oversites 
 
Strength: 
20Nm after 28 days 

C25 CONCRETE CONCRETE STRENGTH GUIDE 

C25 CONCRETE CONCRETE STRENGTH GUIDE 

C25 / ST2 concrete is a multipurpose mix used for both domestic and commercial applications. Commonly used for foundations for houses and extensions. 
 
Uses: 
Un-reinforced strip footings 
Un-reinforced foundations 
General groundworks 
Mass concrete & trench fill 
Bases for extensions, houses or patios 
House floor blinding and pad foundations 
Kerbs, unreinforced house floors (with permanent finish) and patios 
Drainage and filling around manholes or trenches 
 
Strength: 
25Nm after 28 days 

C30 CONCRETE CONCRETE STRENGTH GUIDE 

C30 CONCRETE CONCRETE STRENGTH GUIDE 

C30 is a medium strength concrete commonly used for pavements and external light use applications as well as foundations. This concrete should not be used as a wearing surface. 
 
Uses: 
Drives 
Paths and patios 
Garage and shed bases 
Pavements 
Foundations for houses, extensions and garages 
 
Strength: 
30Nm after 28 Days 

C35 CONCRETE CONCRETE STRENGTH GUIDE 

C35 CONCRETE CONCRETE STRENGTH GUIDE 

C35 / ST3 concrete is mainly used for external slabs for heavy duty applications, where the ground is subjected to heavy loading from foot traffic and/or vehicles. 
 
Uses: 
External slabs 
Heavy duty garages 
Reinforced walls and floors 
Reinforced workshop bases and loading bays 
Unsuspended and unreinforced garage floors 
Unreinforced indoor floor slabs 
Bedding for channels and drains 
 
Strength: 
35Nm after 28 days 

C40 CONCRETE CONCRETE STRENGTH GUIDE 

C40 CONCRETE CONCRETE STRENGTH GUIDE 

C40 concrete is mainly used for structural, roadwork and farm use. 
 
Uses: 
Structural applications 
Industrial applications 
HGV parking 
Agricultural yards 
Septic tanks 
Foundations for traffic sign posts and lighting columns 
Domestic floors used for garages or houses which are partially or completely reinforced and either suspended or ground bearing 
 
Strength: 
40Nm after 28 days 

C45 CONCRETE CONCRETE STRENGTH GUIDE 

C45 CONCRETE CONCRETE STRENGTH GUIDE 

C45 / ST4 is a high strength mix generally not suitable to domestic applications. It is suited to structural, industrial and agricultural projects and is most common in exposed rural areas and heavy duty applications. 
 
Uses: 
Sileage and slurry pits 
HGV Parks 
Aggressive ground 
Stable floors 
Roadworks 
Piling 
Foundations 
Silage and slurry pits 
Roadworks 
Aggressive ground 
HGV Parks 
Stable floors 
Roadworks 
Piling 
Strength: 
45Nm after 28 days 

C50 CONCRETE CONCRETE STRENGTH GUIDE 

C50 CONCRETE CONCRETE STRENGTH GUIDE 

C50 / ST5 is used when concrete is required in harsh conditions where aggressive chemicals or high levels of abrasion are present, and you need a high-performance concrete that can provide the levels of durability and technical performance your specialist application requires. 
 
Uses 
 
Strength: 
50Nm after 28 days 

PAV 1 CONCRETE CONCRETE STRENGTH GUIDE 

PAV 1 CONCRETE CONCRETE STRENGTH GUIDE 

Suitable for pavements and slabs and contains an air-entrainment additive to create small air bubbles in the concrete. This helps protect the surface from freeze-thaw and frost, which is why it’s so good for outdoor paving. 
 
Uses: 
Drives and parking (domestic) 
External slabs (light duty) 
Paths for agricultural, domestic or industrial applications 
Hard standing which is either reinforced or un-reinforced 
House, extension or workshop bases which are reinforced or unreinforced 
 
Strength: 
30Nm after 28 days 

PAV 2 CONCRETE CONCRETE STRENGTH GUIDE 

PAV 2 CONCRETE CONCRETE STRENGTH GUIDE 

Primarily used for external slabs in heavy duty applications where the ground is subject to heavy loads, scraping or rubber-tyred vehicles. 
 
PAV 2 also contains an air-entrainment additive to create small sized air bubbles in the concrete. This helps protect the surface from freeze-thaw and frost. It can also be used with de-icing salts. 
 
Uses: 
Slabs exposed to machinery and industrial vehicles 
HGV yards 
Car parks (high usage) 
Agricultural stores, light storage or commercial buildings with reinforced bases 
Flooring for garages or houses which have metal embedded in them 
 
Strength: 
35Nm after 28 days 

OTHER CONCRETE TREATMENTS & ADMIXTURES 

OTHER CONCRETE TREATMENTS & ADMIXTURES 

FIBRES – fibres can modify and stabilise fresh concrete to reduce settlement and shrinkage cracking. 
 
AIR ADMIXTURES – stable bubbles are formed throughout the concrete mix to provide better resistance during freezing and thawing and improve compaction. Strength is slightly affected but your concrete will have a longer life. 
 
WATER REDUCING ADMIXTURES – workability is improved without significantly affecting air content or setting. These are usually called ‘plasticising admixtures’ and they can improve density and permeability. 
 
ACCELERATOR – the accelerator additive is added during the mixing process. It speeds up the setting and strength at an earlier stage. 
 
FOAM - foam additive is added to a sand-rich low cement concrete to achieve 15/20% air. This flows well and is used for trench filling or low strength void fills. 
 
WATERPROOFER - an additive to make concrete less pourous.  

GET IN TOUCH PALMIX CONCRETE MIXING 

GET IN TOUCH PALMIX CONCRETE MIXING 

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