## Causes for rejection of pipes 

Inspection of the pipes as may be deemed necessary by the Engineer will be made at the place of man- ufacture. Unless a damaged pipe can be repaired as specified below and approved by the Engineer the pipe may be rejected. 

Pipes will be rejected as unsuitable for the Works for any of the following reasons: 

## Defects in unreinforced and reinforced concrete pipes 

Pipes, which exhibit any of the following defects, shall be subject to rejection: 

 A piece of any size broken out of the pipe. 

 Defects that indicate imperfect mixing or moulding of the concrete. 

 Any crack extending through the wall of the pipe and having a longitudinal or transverse length greater than the wall thickness of the pipe. 

 Any shattering or flaking of concrete at a crack. 

 A deficiency greater than 6.5 mm from the specified wall thickness of pipes 750 mm or small- er in diameter, or a deficiency greater than 6 percent from the specified wall thickness of pipes larger than 750 mm in internal diameter, except that the deficiency may be 8 percent adjacent to the longitudinal from joint, provided that the additional deficiency does not lie closer than 20 percent of the internal diameter to the vertical axis of the pipe and does not extent along the circumference for a distance greater than 20 percent of the internal diameter of the pipe. 

 The deficiencies in wall thickness permitted herein do not apply to gasket contact surfaces in gasket jointed pipe. Dimensions and tolerances of such contact surfaces shall be submitted for approval. 

 A variation of more than 1 percent from the true circle of the specified pipe internal diameter. 

 Rock pocked and water pockets in any pipe. 

 Exposure of any reinforcement or insufficient cover to reinforcement. 

 Surface defects indicating honey-comb or open texture. 

 Separation or ”blisters”. 

 Any continuous crack having surface width of 0.25 mm or more and extending for a length of 300 mm or more, regardless of depth or position in the wall of the pipe. 

 The pipe fails the strength test. 

## Repair of imperfections (Bonding mortar repairs with epoxy resin adhesive) 

Unsound or imperfect concrete shall be removed by chipping with a sharp tool. If hand placed mortar is to be used, the edges shall be left sharp and square with the surface. The area to be repaired shall be kept dry. Loose material and concrete dust remaining after the chipping operation shall be removed by means of an air jet. 

Epoxy resins previously approved for such use by the Engineer shall be used as a bonding agent in the manner prescribed by the Engineer. The prepared area shall be primed with the epoxy resin com- pound, care being taken to insure intimate contact with the base material. Mortar shall be applied be- fore the epoxy resin compound sets. 

The mortar used for repair shall contain the same of cement and sand as the mix from which the pipe was made and shall also incorporate an expanding additive. 

