Title:
Kinematics of Dry-Mix Shotcrete
Author(s):
Hugo S. Armelin, Nemkumar Banthia, and Sidney Mindess
Publication:
Materials Journal
Volume:
96
Issue:
3
Appears on pages(s):
283-290
Keywords:
aggregates; shotcrete; velocity
DOI:
10.14359/624
Date:
5/1/1999
Abstract:
Shotcrete is produced by concrete constituents being projected against a shooting surface. However, due to the high velocities developed, it is impossible to observe in-flight particles using conventional tools. As a result, the state of the art on shotcrete kinematics shows a general lack of understanding on the matter, with highly scattered results published in the literature. This study makes use of high-speed filming in an environment of controlled air flow, and using industrial scale shotcrete equipment to measure particle velocities (aggregates and steel fibers) and the influence of the following parameters: aggregate and fiber dimension and shape, air flow, position of shooting and hose/nozzle size. Results obtained allow characterizing dry-mix shotcrete shooting velocities for various conditions, and show aggregate and fiber velocities to be determined by a size parameter (the inverse of the diameter) and an air speed parameter (the air flow divided by the hose cross-sectional area).