Cutting of Concrete


In August 2003 DYNAJET undertook a project for Fasttrack Construction to cut a series of eight access panels for the installation of process vessels. Several factors made this aninteresting project: The cuts had to be made with pinpoint accuracy, large enough to install the tanks, but within the supporting beams installed to strengthen the slab. The plant had to function normally throughout the cutting, without the dust associated with diamond saws. The presence of support tendons in the slab together with the re-bars and the strength of the concrete itself (an estimated 45 newton) made this job a challenge. Ultra High Pressure water at 40,000 psi was used with garnet entrainment to make to the cuts.

Five circular cuts of 2.15metre diameter and three rectangular cuts of 2500mm by 1700mm were made. Each was completed well within the 25mm tolerance allowed.

View from below the slab(right) showing two completed circular cuts with a third already filled by a tank.


A circular cut in the 200mm thick slab. The entire section weighing over 2 tons has been removed to allow the tank to be installed.


A rectangular cut piece is removed from the slab. Masonry bolts were screwed into the cut section to support it during cutting and assist in removal.


A section of tensioning tendon severed by the abrasive cutting process. The 100mm tendon has six strands of braided wires and an outer cover.


A cutting jig used for making the circular cuts.


A cut section showng the severed tendon.


A section of a circular cut


A section of a rectangular cut