The method determines the time t AST M and heat flow QAST M according to ASTM C1679, i.e., the method determines a maximum heat flow (after an initial cutoff time parameter that excludes the initial heat due to ettringite formation) and then finds the time at which the heat flow has a value of 50% of the maximum heat flow at the left flank of the main hydration heat event. The method returns a pandas.DataFrame with the time and heat flow values.