Tuesday, January 22, 2008

Bahamian Concrete 101



After our day and night of rain we woke to a lovely day. Our holes were filled with water but Pete Davidson loaned us a bilge pump and we pumped one of them out and started to work. In the US we typically call the concrete compnay and tell them how many yards we need, they back the truck up to the site, and start pouring directly from the truck. Not so here on Andros.

Ricardo is the maintenance chief here at the staion,working here at Forfar for going on 22 years now. He gave gave us a lesson in how concrete is mixed here on the island, instructing us on the finer points of dry mixing the materials first then forming a tray from the dry mix, adding water and turning it into a strong concrete mix. In the US we would add small gravel to the mix. Here we simply drop in some concrete mix and then drop in the large baseball to football size stones to the mix. Repeat, repeat, repeat. The sand here is carbonate based (rather than silica)as is the stone we are tossing in. In addition the carbonate stone is pourous and irregular, so it sucks up the concrete for a strong bond. Since carbonate is the base material of Portland cement the final Bahamian concrete pour is super strong.