Ready To Use
Concrete mix that is ready to use only requires the addition of water and mixing before its application in post holes. You can mix an entire bag at a time in a wheelbarrow and add to each post hole, set the post and continue filling the hole. This type of concrete mix dries and cures in about 24 hours, so that you do not have to rush to fill the post holes. After the posts are set, you need to wait 24 hours before securing the fence material to the posts so that the posts remain level both horizontally and vertically.
Fast set concrete mix requires adding water and mixing prior to its use. Application of this type of concrete mix needs to be quick as it sets and cures within 25 to 45 minutes depending on the thickness of the mixture. When you use fast set concrete mix, you dig all of the post holes at once and then mix the mixture. You mix only one bag at a time so that it does not start to harden in the mixing container. If the concrete mix starts to harden before putting it into the post holes, it becomes heavier and more difficult to shovel into the holes. It may also be lumpy and contain air pockets that reduce the strength of the mixture. You only need to wait 45 minutes after setting posts to begin adding the fencing material.
This type of concrete mix is made especially for fence posts. Fast setting concrete mix does not require mixing with water. There is no mixing container or wheelbarrow to clean at the end of your project. You dig the post hole and prop the post level in the hole, then pour the dry concrete mix out of the bag around the post. Ground moisture absorbs into the mix for it to cure. You may add a small amount of water to the hole first to dampen it and a small amount of water on top of the mix for faster curing. Fast setting cement is the quickest method to steady fence posts because it cures in 20 to 40 minutes.