The P-Cal is a high performance semi-adiabatic calorimeter with high efficiency insulation to achieve close to adiabatic conditions. The P-Cal is the only high performance semi-adiabatic calorimeter that is so portable it can easily be carried in concrete delivery trucks or other field applications. P-Cal 1000 can be used to test concrete, mortar or paste in a standard 4”x8” (100 mm x 200 mm) cylinder or any standard container that fits inside. P-Cal measures changes in temperature, a proxy for heat released as cement is hydrating. Because of its ultra-high performance insulation, it closely mimics the conditions encountered in the core of mass concrete applications.