An engine and high pressure pump are mounted onto a wheeled chassis. Each anode is inserted into a drilled hole in the layer and is electrically attached to the rebar in the same or an adjacent hole by a steel pin which is attached to the reinforcement by arc welding or by impact. Each projection has a tip terminating the projection before an edge of an opposing side of the opening, and the tips of adjacent projections extend past each other both in an inactive position, wherein all projections are placed in the same or in parallel planes, and in an active dispensing position, wherein the projections are turned upwards.