System for underwater repair of cracks in concrete

摘要

A hardenable sealant composition, apparatus for application, and method of implementation are provided for repairing cracks in concrete covered by water. The apparatus of the invention employs a sealant reservoir formed with a high pressure cylinder having twistlock ends. The cylinder is filled with a cement compound that will subsequently harden under water. The cylinder contains a piston and is coupled at one end to a high pressure pneumatic hose. The other end of the cylinder is connected to a material delivery hose which in turn leads through a manually operable metering valve assembly to a hollow injection needle. Holes are drilled into the surface of an underwater concrete structure in which a crack appears, and the injection needle is inserted into the holes, one by one. The sealant composition is formed of a resin, a resin hardener, white cement and underwater cement. It is extruded from the sealant reservoir under the control of the metering valve. As the sealant is expelled from the needle in each hole it enters and permeates the crack throughout the length and depth of the crack. If the viscosity of the sealant composition to be extruded into the cracks warrants, surface sealant may be applied along the length of the crack before injection of the sealant into the holes to prevent the injected sealant from emanating from the crack.