Description
Australian Builders High Strength Concrete is a dry mix of cement, 7-10mm aggregate and sand for projects where a higher concrete strength is required. The product data sheet gives a typical compressive strength of more than 30 MPa at 7 days and more than 40 MPa at 28 days, tested to AS 1012.9.
It suits footings, slabs, paths and driveways, decking and fence or pergola posts, and other work where your plans call for a higher-strength mix. Where an engineer or building surveyor has specified a strength grade, follow that specification.
As a guide, use about 2.4 litres of clean water per 20kg bag and keep water to the minimum needed: extra water reduces strength and increases porosity. About 100 x 20kg bags make 1m³ of concrete.
Technical Specifications
| Composition | Cement, 7-10mm aggregate and sand (approx. 1.5 : 2 : 2 by volume) |
|---|---|
| Compressive strength (typical) | >30 MPa at 7 days, >40 MPa at 28 days (tested to AS 1012.9) |
| Water | Approx. 2.4 L per 20kg bag |
| Yield | Approx. 100 x 20kg bags per 1m³ |
| Storage | Up to six months, dry and protected from moisture |
| Pack size | 20kg bag |
Where to Use
- Footings and foundations
- Slabs, paths and driveways
- Decking, fence and pergola posts
- Other work where your plans call for a higher-strength mix
How to Apply
- Confirm the required strength: check the job’s specification before starting.
- Prepare the area: excavate and form up to the required depth.
- Mix: empty the bag into a wheelbarrow and add water gradually, about 2.4 litres per 20kg, using the minimum needed for a workable mix.
- Place and finish: use the concrete immediately after mixing. Avoid overworking the surface and do the smooth finish after the initial set, within about 2 hours.
- Cure: start as soon as the concrete is finished. Keep it moist under plastic sheeting or hessian; the first week matters most.
Important Notes
- Wet cement is alkaline and can burn skin and eyes. Wear gloves, eye protection and a P2 mask, avoid breathing dust when opening or mixing, and wash it off skin promptly. See the Safe Work Australia guidance on cement and silica dust.
- Cement, sand and aggregate contain crystalline silica. Keep the material damp where you can, avoid breathing the dust, and wear a P2 mask if it is dry and dusty.
- Follow an engineer’s or building surveyor’s specification for structural work.
- Extra water reduces strength and increases porosity.
- Store dry; the manufacturer gives a storage life of up to six months.
- Pickup only from our Keilor East yard.
