Calsil or Council brick?

[BrendanLovesPizza]

Hi All,

Please can someone with knowledge of Australian bricks shed some light on the brick in the photo.

Are they a "calsil" brick or a "council" brick. I may have misinterpreted a common bricky term at some point in my travels.

They are hard, yet crumble dont shard like a paver. They are very white, sandy, and heavy.
I need them to make a chimney arch, and dont want them to fall apart in 6 months time. Will they hold up to riggers of heat stresses.

Cheers all.

[Toomulla]

Re: Calsil or Council brick?

Calsil is basically concrete being lime silica sand and water it will deteriorate at temps over 450c so I would not use for a chimney, they also are very adsorbent