How to make a concrete bench
Part 3. Make the concrete
This concrete bench will take about three-quarters of the average heavy-duty wheelbarrow full of concrete to make.
For this project we are going to make the concrete mix a little bit wetter than normal and add a slightly larger ratio of cement to the mix than usual. This will allow the concrete to get to every corner of the form without too much of a problem. If there is any ponding i.e. liquid puddles of sorts on top of the mix when finished (mixing), then it is too wet. If that is the case, mix in some more aggregate and cement. Likewise, if the mix is too dry, add water. The ready-to-pour mixture should be a good even, flowing consistency.
Three ingredients make the concrete: aggregate, cement, and water.
Aggregate (in this sense and for this purpose) is a mixture of different size stones ranging from
20mm (¾") diameter maximum, down to the size of a grain of sand. The smaller stones fill up the cavity created by the bigger stones.
You can make your own aggregate by mixing 3 parts gravel and 2 parts sand.
The mixture to make the concrete bench
A standard household plastic 2 gallon (9 or 10 liter) bucket.
Four and a half buckets of aggregate.
One bucket of cement.
Approximately ⅝ of a bucket of water. This can vary depending on the dryness or dampness of the aggregate.
Start with ½ a bucket and add more if needed.