Frequently, shotcrete contractors are required to shoot test panels at the beginning as well as throughout projects. Several tests are performed from these panels; however, compressive strength testing is the most common. This article will primarily address compressive strength testing. At some point, every contractor has missed a required break strength on a core extracted from one of their panels. Frequently, those bad results are not caused by bad material or poor workmanship. They are caused by poor test panel handling and improperly performed test standards. Often, the causes of those bad test results could have been easily avoided. Let’s discuss some of the more common test panel mistakes witnessed in the field