Abstract
A new apparatus, an improved reaction calorimeter was designed and constructed to determine the reaction rate of contact hydration of cement in a short time. The calorimeter consists of twin cells with comb-like agitators in them: a sample cell, wherein hydration reaction takes place, filled with cement and water and a reference cell filled with a reference material. A thermocouple probe is attached at the center of each cell to detect the temperature difference between the cells. The differential output from the thermocouples acts as feedback signal to control the input to an electric heater in the reference cell to compensate the temperature difference between the cells.
Input power to the heater in the reference cell agreed with the calibration heat supplied in the sample cell within 3%. The heat rate curve obtained for contact hydration of Portland cement coincided with that determined by the time differentiation of a reaction thermogram which was obtained using an isoperibol calorimeter and corrected by Newton’s law of cooling.
https://ror.org/0112mx960 
