Determination and Application of Optimum Abrasive Mass Flow Rate of Abrasive Waterjet

Abstract

Abrasive waterjet can be effectively used in cutting reinforced concrete (RC) piles. The cutting performance increases with abrasive mass flow rate, but as the abrasive mass flow rate increases, damage of abrasive particles also increases. Using optimum abrasive mass flow rate in cutting RC piles, which is determined by considering damage of abrasive particles, can improve cutting performance. In this paper, quantification of effect of abrasive waterjet parameters on cutting performance is simplified by using maximum kinetic energy as medium to relate abrasive waterjet parameters to cutting depth. The damage of abrasive particles during acceleration is related to mixing tube diameter, abrasive material properties and gradation, and is independent of pump pressure, water mass flow rate, transverse speed, standoff distance (SOD), jet impingement angle, and number of cuts. It is found that damage of abrasive particles leads to a reduction of effective kinetic energy used in cutting RC structures. The model for prediction of optimum abrasive mass flow rate is proposed by introducing coefficient of momentum transfer, which considers loss of kinetic energy during acceleration. The optimum abrasive mass flow rate calculated based on proposed model is then used in field test, which shows obvious improvement of cutting performance.