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
I used one part Cement ALL, 3 parts perlite, half a part sand, a pinch of fibre, and two ounces of the liquid pigment.
With a greater ratio of perlite, I found this mix felt dryer and not as smooth and sticky like the previous three.
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.
It didn’t seem to settle as well with the recip saw so, I also tapped the form with a wooden mallet.
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.