The concrete was poured on Friday after the rain-out on Thursday. The concrete has 50% fly-ash/slag replacement for the cementing material. Fly-ash and slag are the waste byproduct from coal fired power plants. According to the US EPA, Portland Cement (the binder used in concrete) is the 3rd largest producer of CO2 emissions in the US annually. Fly-ash/Slag are also binders, and because they are waste byproducts no new carbon is added to the atmosphere when you use it as a replacement. The kicker is that when using a combination of cement, fly-ash and slag after 60 days out you get even STRONGER concrete. The only downside is the concrete takes a little longer to fully cure, and is a little harder to ‘work’. Because many developers / builders are focused on the short term flipping of houses they’ll forgo using fly-ash. It seems like a silly trade-off to worry about a few extra weeks of curing when the concrete itself is going to last 100 years. . . but that’s what we sometimes do I guess.
The concrete also was colored- ‘charcoal’, (just for aesthetics). Here are some pictures. Most of the crew of general contractor are eastern European, so there is a lot of Polish/Russian spoken on the job site. Dobry in Polish means good or strong. With my penchant for languages (Ha!), we say a lot of things are ‘Very Dobry’.