The paper reports about the generation and testing of an air-entrained waterjet for concrete demolition applications. Experimental results on concrete samples impinged by conventional waterjets and the air-waterjet show three essential features of the material removal process. First, the depth of cut is not influenced by the air addition. Second, the entrainment of air significantly affects the material removal rate. Third, there exists an optimum air flow-rate for a maximum material removal rate. Based on results of mercury-penetration measurements and acoustic-emission tests, a first phenomenological model (based on the formation of water slugs due to the air suction) is developed.