Browse Forums Paving & Concreting 1 Nov 16, 2014 3:04 pm Ive seen this a number of times - the concrete used for driveways and paths is much softer than the concrete used for house pads. It damages easily. When requesting concrete to be laid, can you specify how hard you want it? ie house pad hard? Re: Why is paving concrete so soft? 2Nov 16, 2014 5:29 pm Generally the specified strength for either application can be the same. The strength or hardness of concrete when it has cured is mainly related to the water cement ratio in the mix. (also see http://www.anewhouse.com.au/2014/03/con ... tra-water/) The concrete for the house slab generally has a super plasticiser added to allow it to be delivered by concrete pump. This makes it very workable (easy to place) without affecting the water cement ratio. For paving concrete placed straight off a truck its cheaper to avoid using a pump, and paying for the cost of the super plasticiser. The concretors, if not supervised, add water to the mix on site to increase the workability which results in a lower strength concrete. The Harder You Try - the Luckier You Get ! Web site http://www.anewhouse.com.au Informative, Amusing, and Opinionated Blog - Over 600 posts on all aspects of building a new house. Re: Why is paving concrete so soft? 4Nov 17, 2014 8:32 am IT shouldnt be weaker if the mix is from a cement Co. As others have said, mostly likely it will be weak due to too much water added by the finisher. 20-25MPa and RF62/RF72 is fine for driveways carrying passenger vehicles. 32Mpa and RF82+ is recommended for driveways carrying trucks. I've dug some footings to embed a post anchor into. My holes are around 450mm deep which I'll put a 200mm stirrup into. The bottom of these holes seem firm enough. … 0 3315 As most others have posted above the install isn't compliant. The pipe is meant to be covered in loose soil or sand, the pipe has holes in it that leaks out a termicide… 10 5727 That sucks! Hope it all works out. Good to move away from steel anyway for all your reasons, but it's also thermally poor. 16 17871 |