Lightweight Concrete Garden Boxes – Pt 3.5 Perlite, Portland & CSA Cement

adding Perlite

CSA version of the perlite concrete mix
Lightweight Perlite CSA Concrete Ingredients

This blend then uses CSA cement, perlite, sand, and glass fibre. And I’ll add some black colour this time. I didn’t have pure CSA cement but a mix called Cement ALL. It already has some fine sand in the blend so I modified my proportions to accommodate for that.
The CSA based cement is stronger than portland so I figured I could use more perlite because of that. And with the Cement All having sand in it already, I reduced the amount of sand I would add to this blend. And hope that it would work.

Lightweight Concrete  – 4th Blend Test

Lightweight Perlite Concrete blend formulation
Lightweight Perlite CSA Concrete Formula

I used one part Cement ALL, 3 parts perlite, half a part sand, a pinch of fibre, and two ounces of the liquid pigment.

CSA concrete formula with perlite added
What does CSA stand for?

With a greater ratio of perlite, I found this mix felt dryer and not as smooth and sticky like the previous three.

cement color added to perlite concrete mix an a wheelbarrow
Pouring black dye in wheelbarrow

Cement ALL is fast setting so I worked quickly. Blending the sand and perlite with water first, then adding the Cement ALL and more water.

vibrating wet concrete mix to settle it
CSA Perlite wet concrete being vibrated to settle in form

It didn’t seem to settle as well with the recip saw so, I also tapped the form with a wooden mallet.

trowel smooth the wet concrete in the moulds
CSA concrete sets up fast. Must smooth quickly with a trowel

In about 45 minutes the CSA concrete was hardened, warm to the touch, and a white haze was forming as it was drying. I cured it for one hour by sprinkling it with water every 10 minutes or so.

Water Curing

water curing the CSA concrete perlite mix
Water curing CSA Perlite Concrete

4 thoughts on “Lightweight Concrete Garden Boxes – Pt 3.5 Perlite, Portland & CSA Cement”

  1. I’ve looked through all the various posts, but I can’t seem to find any specifics on the volumes of materials used per panel, only the ratios. I’d like to estimate how much of each material I need before I start the project. E.g. how far does one bag of cement go, etc.

    1. I was doing some “by eye” estimations as I was going. I was using a few form sizes too. I think on the blog pages I listed the weight of the panels and the reference regular concrete one. You might have to work backwards to get what you need. Also, there’s online concrete calculators that will tell you how much you need per volume. Plug in the size of the panel roughly and it will tell you.

  2. Hi Kent..THANKS for the very informative and detailed information in your videos and website..I was wondering which grade of perlite you used? Have you experimented with the different grades?

    1. I am not sure the exact grade of perlite I used. I bought it in a big bag from a local garden supplier. In the video I have a closeup (if I remember correctly) showing the size of the granules.

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