18 of 49 Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 05: Earth Works, Pipe Works and Ground Improvement  Causes for rejection of pipes  Defects in unreinforced and reinforced concrete pipes  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.  5_Vol3_d4.3_Section 5 Earth and pipe works_en_GIR_rev6.docx   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.  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 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.   Any shattering or flaking of concrete at a crack.   Any crack extending through the wall of the pipe and having a longitudinal or transverse  length greater than the wall thickness of the pipe.   Defects that indicate imperfect mixing or moulding of the concrete.   A piece of any size broken out of the pipe.  Pipes, which exhibit any of the following defects, shall be subject to rejection:  Pipes will be rejected as unsuitable for the Works for any of the following reasons:  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. 