What is the purpose of fly ash? How much calcium should be used in cold weather pouring?
A. From our Expert, Daniel Herzner of DecoCrete Depot. Fly ash is a byproduct of burning coal. It is commonly used as an admixture to make the concrete stronger, more durable and easier to work with. It is also a “green” building material and a terrific way to get the most from natural coal resources. Additionally, there are a tremendous number of major building projects taking place around the globe which tend to put a real strain on global supplies of cement (the “glue” of concrete). So, fly ash also provides a great way to extend naturally mined cement resources. Calcium is frequently used as a low cost set accelerator (it helps the concrete set up more quickly and promotes early strength). Its relatively low cost may be its only advantage. NEVER use calcium chloride in integrally colored concrete. It tends to attack the pigments, causing blotchiness and color fading. It also has a tendency to cause efflorescence. In order to side step any potential issues that calcium can cause, it
