What is the initial setting timing of concrete?

Initial setting time of Concrete depends on the type of Cement used, like for Ordinary Portland Cement (OPC) Initial setting time, is 30 Minutes. Whereas, for concrete setting time depends upon the Admixtures added in Concrete. Usually, it's preferred that concrete should be laid within 3 Hours of it's dispatch from Concrete mixer or Concrete plant, because the hydraulic (Chemical) reaction between CaO (Calcium oxide) and H2O (Water) starts. Thus, any sort of delay will affect workability and Compressive strength.