Cemix Fastcrete can be used for any concrete project requiring fast setting times with low structural requirements. The average Kiwi Fence stands between 1.2m - 1.8m high supported by 100 x 100 H4 posts. Cemix recommends 2 x 20kg bags per post to hold in place prior to the placement of structural concrete.

Typical Applications & Uses:

  • Letter box posts.
  • Small signs.
  • Low fence posts.
  • Temporary hold of posts before topping with Cemix Multicrete or Cemix Maxcrete.


  • No mixing required.
  • Fast setting.
  • Easy and convenient to use.

20kg & 25kg


Dig a hole and place your post in it. Keep the post off the ground to prevent rot and also apply Cemix® Bituproof Plus on the part of the post that will be sub ground. Completely wet the hole and compensate for any ground drainage that might soak up the water required for Cemix® Fastcrete. In sandy soils, line the hole with plastic. Pour 2.5 – 3.5 litres of water per bag of Cemix® Fastcrete. Position the post in the centre of the hole. Evenly and slowly pour the dry contents of the Cemix® Fasrcrete around the post. Ensure the concrete gets wet progressively as you pour. Do not empty the bad quickly as this will lead to dry patches and you will have to rod to allow for water penetration. If any dry product is visible on the surface, sprinkle water over to dampen.

Due to the fast setting time of Cemix® Fastcrete, do not mix in a concrete mixer or wheelbarrow.

After a minimum of 15 minutes the hole can be topped up with earth and after one hour the post can withstand wire straining or similar pressure. It is recommended that a third of the post should be below ground. The diameter of the hole in the ground needs to be a minimum of twice the diameter of the post.


Cemix® Fastcrete consists of a uniformly blended, properly proportioned mixture of stone, gravel, sand, Portland cement and other admixtures approved for use in concrete to improve workability, performance and the fast set of the product.

Technical Data:

Appearance – grey concrete powder

Strength (MPa) – 10MPa @ 7 days, 15MPa @ 28 days.

Application Temp – 5oC – 30oC

Yield / Coverage - .0096m3 per 20kg bag

Packaging – 20kg & 25kg bags

The data shown above reflects typical results based on laboratory testing under controlled conditions. Reasonable variations may occur on site.


Cemix® Fastcrete in a cool dry area and use within 6 months.


Clean all tools with water & brush immediately after use.