Pouring Concrete

Saturday, Jan. 18, 2014

Today I faced up to the challenge of mixing and pouring concrete.  This is the first time I have tried doing anything with concrete beyond setting fence posts.  But the project was small enough that I didn't feel apprehensive about it.

Today's objective was to build a concrete footing, 5 and 1/2 inches wide and four inches deep, on the south side of the basin, even with the top of the basin wall.  I had bought the concrete mix, Quikcrete, the previous weekend, had built a form for the footing, and laid four inches of sand as a base.  All that remained was to mix the concrete and place it into the form.

I used a wheel barrow to mix the concrete, one 50 pound bag of Quikcrete at a time.

I didn't dare just pour the concrete into the form from the wheel barrow.  I used a shovel, and placed one shovel full at a time into the form, trying to fill the form evenly up to the top.

Following the advice of my concrete book, I used the shovel to work the concrete mix into the space under the rebar, attempting to fill the form evenly, and used a small piece of wood to "screed" the excess from the top.  Also tapped the side of the form with a hammer, which the book says "draws finer aggregates in the concrete against the forms, creating a smoother surface on the sides."

Here I have finished placing the concrete mix, and "bleed water" is starting to appear.  Again quoting the book, "Timing is the key to an attractive concrete finish.  When concrete is poured, the heavy materials gradually sink, leaving a thin layer of water--known as bleed water-- on the surface. To achieve an attractive finish, it's important to let bleed water evaporate before proceeding with the other steps."

The next step would be to smooth the surface with a "float", a tool that is essentially just a flat piece of wood with a handle.  It was already getting dark, and I needed to wait for the bleed water to evaporate, which takes an hour or two, but I couldn't wait until the next day.  By the next morning the concrete would be set and impossible to smooth.

I set up work lights, and did the float work well after dark.

Sunday, Jan. 19, 2014

The smoothing did not turn out very good.

I would not want a sidewalk that looked like this.  But, fortunately, this concrete will not normally be visible.  Apparently there is some real skill involved in producing a nice concrete surface.