Grout Mixture Experiment
I mixed 5 tablespoons of unsanded grout with various additives in small disposable plastic cups and let them dry for a week.
I recorded how badly it cracked after one week of drying and how absorptive it was.
I experimented with:
- Uncrushed perlite (called Regular Perlite below)
- Perlite lightly crushed with a rolling pin (called Perlite Powder below)
- Perlite finely ground in a coffee grinder (called Ground Perlite below)
- Sand (regular sand meant for kid's sandboxes)
Pure un-sanded grout: No cracks Absorbed extremely slowly and moisture did not seem to spread far
1/6 Perlite Powder + 1/6 Regular Perlite: No cracks Absorbed at an average rate
1/6 sand + 1/6 Regular Perlite : No cracks Absorbed at an average rate
1/6 sand + Perlite Powder: Cracked Absorbed at an average rate
1/4 Regular Perlite: No cracks Absorbed at an average rate
1/3 Regular Perlite: Cracked Absorbed quickly
1/4 Perlite Powder: Slight crack Absorbed at an average rate
1/3 Perlite Powder: Slight crack Absorbed at an average rate
1/2 Sand: Cracked Absorbed at an average rate
1/3 Sand: No cracks Absorbed at an average rate
1/4 Sand: No cracks Absorbed slowly and somewhat unevenly
1/3 Sand + 1/6 Regular Perlite: Slight crack Absorbed at an average rate
1/3 Sand + 1/6 Perlite Powder: Cracked Absorbed at an average rate
Definition for cracks:
No cracks = no cracks of any kind.
Slight crack = a tiny hairline crack that was barely visible.
Cracked = a crack that went all the way through, and an ant might be able to get a good enough grip to chew on it. The crack was quite obvious.
The grout mixture was only about 5mm thick, so that may account for some of the cracks. If it was thicker some of the cracks may have not occurred.
Perlite Powder seems to lead to a higher cracking possibility.
Sand settles quite quickly, which may affect the absorbancy on the reverse side. I left these in the cups and did not remove them when testing the absorbancy.