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A typical mortar mix ratio is 1 cement : 3 sand. But what is the water ratio? Is it 0.5:1:3?

Would a 0.5:1:2 ratio be a stronger mortar?

Our next door neighbor has a dog that digs like a pro. The dog somehow manages to dig underneath some parts of our wire fence netting and get through. So I have thought of filling the holes with mortar.

I previously tried to fill the holes with concrete made with 0.5 water : 1 cement : 2 sand : 3 gravel, but the mix I made easily crumbled apart. Could that be because I bought gravel made of 0.5inch stones?

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Your mix was too dry It's hard to add to much water but being to dry it will crumble –  user31779 Jan 17 at 8:46
It also takes several days to harden and probably 2 weeks to cure. You'll need something (wooden stakes, etc) to keep the dog and others from disturbing the mixture until it has hardened. For this situation I would recommend sand, and gravel. Maybe try some quikcrete with stakes, or wooden boards to prevent the disturbance for a couple weeks, until full curing. –  Ben Sep 12 at 15:32

4 Answers 4

The less water the better, to a point. Excess water will weaken the mix. At some point in the other direction, there is not enough water for the hydration process(around 0.25:1 water:cement). In general though, to have a workable mix, there will be enough water for hydration. Use as little water as possible to make a workable mix, around 0.45:1 is fine. Don't use mortar for bulk fill, it's a waste of cement. The gravel in concrete is just filler, saving cement.

The concrete you mixed is sort of the standard DIY ratio, I don't know why it didn't work. While 0.5" gravel is a bit small, it can't be the reason for crumbling. Perhaps the cement was old? It may have absorbed enough humidity to partially hydrate, but not so much that it bound together.

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The half inch stones aren't the problem.

It was supposed to be 1:1 1/2:1.

  • 1 cement
  • 1-1/2 sand
  • 1 gravel

The concrete needs water - not too much - but should be a moderate amount for it to make the cement react rapidly.

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It is virtually impossible to specify the proportion of water in a concrete mix due to the wide range of moisture content in the sand used, Regarding "old" cement powder - if kept completely and utterly dry it will work fine after literally years. The only downside of using old cement is that the Chromium additives change from relatively harmless to relatively harmful. In my opinion if proper precautions are taken (e.g. respiratory and skin protection) this should not be a problem. Best mix to fill up these holes would be 1:4 ratio by volume cement to sand/ballast mix (20mm stones in the ballast). The total volume of cement in each hole must be at least 1 litre.

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Dry mix ratios can be played with. A slump test tells you to add more or less water. –  Mazura Apr 17 at 1:10

The correct mixing ratio would be 1:1.5:1 — 1 cement : 1.5 sand : 1 gravel stones with 0.4 water. If you use more water it will leave holes (porosity of the mortar), and if you use less water, it will not lead to hydration.

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