Empirical variations in single particle impact breakage distribution data of eleven types of raw and one type of cement clinkers crushed in High Pressure Grinding Rolls (HPGRs) were used to analyse the size and energy level dependency of clinker breakage. Breakage distributions of the impacted particles, analysed through size normalized distribution curves, were used to reconstruct breakage functions using the conventional t10-tn family curve approach. Results showed that, size normalized breakage functions become self-similar (falls into the same pattern) at energy levels higher than 1 kWh/t. Empirical t10-tn family curves were proposed to reconstruct breakage functions which could be used in models of cement grinding tube mills. (C) 2014 Elsevier B.V. All rights reserved.