Want to have a library of concrete basics at your fingertips? Then get the new app Concrete Now!, developed by BASF Master Builders. This resource was developed by the same folks that appear each year at the World of Concrete Breakfast with the Experts.
Currently there are four "chapters" on air in concrete, set time, slump, and finishability, each with interactive subsections that lead the reader through the subject. For example, under set time, start with the difference between initial set and final set, then go through the influence on set time of cementitious content, water, temperature, and admixtures. An interactive dial gage shows you the impact on set time of adding fly ash or slag or increasing the cement content.
There are also two concrete calculators for determining the surface evaporation rate or the concrete temperature based on the temperature and quantity of the ingredients in the mix. And there is, of course, a list of all Master Builders admixtures detailing how each affects the concrete and where and when it should be used.
And best of all, it's free! You can download the app at the Apple store, Google Play, or the Windows app store.