Made by Cement Australia
Concrete · Gates and fencing
PROSTRENGTH Rapid Set Concrete 20kg
No-mix rapid set that reaches up to 40MPa at 28 days, for gates, professional fencing, signs and load-bearing posts.
Comes on pallets of 48 or 84 × 20kg bags.
1 bag (less than a pallet).
Lead time: Approx. 1 to 2 working days
Code: 200842060
Available to order from Allmat. Click and collect or delivered across Adelaide.
How many bags do I need?
Work it out with the free Allmat concrete calculator.
About PROSTRENGTH Rapid Set Concrete 20kg
A rapid set concrete for jobs that need more strength. It goes in without mixing and reaches up to 40MPa at 28 days, twice the strength of a standard rapid set mix. It suits professional fencing, gates, commercial and road signs, retaining walls and sporting equipment.
- Strength
- Up to 40MPa at 28 days (AS1012 methods 8.1 and 9)
- Approved
- TMR MRTS14, frangible support posts
- Hardens
- In 30 minutes
- Supports off
- After 30 minutes
- Water
- 2.0L per bag
- Mixing
- None, just add water
- Temperature
- 10°C to 35°C
- Yield
- About 110 × 20kg bags per m3
Best for
- Professional fencing and gates
- Load-bearing posts
- Commercial and road sign posts
- Retaining walls
- Sporting ground equipment
Not for
- Placing below 10°C or above 35°C
- Aluminium posts or poles that are not primed or sealed
- Batching in a concrete mixer, barrow or bucket: it hardens quickly
- Adding cement, sand, other aggregates or admixtures
How to use
- If the hole is dry, wet it first. Have everything ready before you start, as it sets fast, and keep out of direct sun on hot days.
- Set the post upright in the hole and support it so it stays plumb.
- Pour 2.0L of clean water per bag into the hole. Add up to 0.2L more per bag only if needed. Extra water costs strength.
- Without delay, tip half the bag in around the post and tamp. Follow with the second half, tamp again and only add water if it is needed.
- The supports can come off after 30 minutes. Wash your tools with water straight after.
Storage & safety
Keeps about 6 months from manufacture, sealed, dry and off the ground. Do not use a bag that has gone hard. Wear dust-proof goggles and PVC or rubber gloves. Each 20kg bag is a two-person lift. Storing and handling bagged cement.
How many bags?
About 2 × 20kg bags for a 200 × 600mm post hole with a 90x90 post, by our estimate, allowing 100mm of gravel and 10% extra.
Not sure this is the right concrete? Compare the four bagged concretes.
Documents
The manufacturer's own sheets. Open one to read it on the page, share it or download the PDF.
PROSTRENGTH Rapid Set Concrete questions
Up to 40MPa at 28 days when tested to Australian Standard methods (AS1012), which Cement Australia says is twice a standard rapid set mix.
After 30 minutes. Be ready to work quickly, and avoid direct sun on hot days, as heat changes the set time.
Pour 2.0L of clean water into the hole for each bag. Only top up, by no more than 0.2L a bag, if the mix needs it.
Both go in without mixing. PROSTRENGTH reaches up to 40MPa, twice a standard rapid set mix, hardens in 30 minutes and the supports can come off after 30 minutes. Standard Rapid Set needs 1 hour and is for non-structural posts only.
Cement Australia's data sheet puts it at about 110 × 20kg bags per cubic metre. The fence post calculator, linked below these questions, works out the bags for your hole and post size.
Linked from these answers: Fence post calculator
Sources and guidance
The product information on this page comes from Cement Australia's published product data sheets, safety data sheets and website (see Documents above). It is general guidance only. Other manufacturers may give different advice for their own products, so always follow the instructions on the bag and the product's data sheet. Structural work, such as footings for buildings, must follow your engineer's design and the relevant Australian Standards.
You may also need
Often ordered with this product. Use + Add to pick the option and quantity and put it on the same quote.
Rapid Set Concrete 20kg
No-mix concrete for fence posts, clotheslines and letterboxes. Starts to harden within 15 minutes.
PROSTRENGTH Extra Strength Concrete 20kg
High strength concrete mix, designed for up to 50MPa in lab tests. Walk on it after 24 hours.