水工隧洞混凝土缺陷處理施工措施

1、-. z.Karuma Hydropower Plant and Associated Transmission Line WorksManual For Concrete Defects Repairing Of TRT LiningRef: M-GE-GE-005(Revision 0)THE EMPLOYER:THE EPC CONTRACTOR:THE government OF REPUBLIC OF UGANDA,SINOHYDROCORPORATION LIMITEDREPRESENTED BY THE MINISTRY OF ENERGYAND MINERAL DEVELOPE

2、MENTOctober,2016-. z.CONTENTTOC o 1-2 h u HYPERLINK l _Toc11527 1.Purpose PAGEREF _Toc11527 1 HYPERLINK l _Toc23593 2.Main Defects of Concrete Works1 HYPERLINK l _Toc22582 3.Major Techinical Measures For Repairing1 HYPERLINK l _Toc9846 3.1 Dislocation1 HYPERLINK l _Toc2143 3.2 Grout Leakage2 HYPERLI

3、NK l _Toc16085 3.3 Honey b2 HYPERLINK l _Toc85 3.4 Pitted Surface2 HYPERLINK l _Toc24800 3.5 Cavity2 HYPERLINK l _Toc26717 3.6 Local Depression and Groove3 HYPERLINK l _Toc26717 3.7 Reinforcement E*posure3 HYPERLINK l _Toc26717 3.8 Crack and Cold joint4 HYPERLINK l _Toc26717 3.9 Protruded Reinforcem

4、ent End5 HYPERLINK l _Toc5386 4.Quality Control5-. z.PurposeTo insure concrete quality shall meet standard and contract requirements after concrete repairing procedures.Main Defects of Concrete Worksmon defects maybe occur in concrete works mainly include dislocation,grout leakage, honey b, pitted s

5、urface, cavity, local depression and groove, reinforcement e*posure, cold joint, cracks, protruded reinforcement end and so on.Major Techinical Measures For RepairingOnce the type of the defect is identified, relative special-assigned personnel will be arranged to treat the various defects occur in

6、different construction positions. DislocationRepair methods for dislocation mainly includechiseling and polishing, then backfilled with equivelent strenth as the concrete. Different methods will be adopted according to different situation. 1) If the dislocationis not more than 20mm, grinding machine

7、 shall be used for polishing the surface to forma slope of 1:10. 2) If the dislocation is more than 20mm, pneumatic pick shall be used to trim the surface to form a slope of 1:10. 3) If only appearance requirement, fine aggregate concrete or mortar which is one grade higher than the original concret

8、e shall be used for pacting and leveling the surface.Grout Leakage The leaked grout shall be cleaned away. If in some positions, its hard to remove the groutingartificially. In such portions, grinding machine will be used for polishing and triming the surface and then use high pressure water to flus

9、h the surface. Honey b To chip away the loose material in the honey b artificially or by pneumatic pick, and then use high pressure water flush the surface. Fine concrete or mortar, one grade higher than original concrete, shall be used for repairing the defect in the sequence of leveling, paction a

10、nd troweling.If honey b occurres on overflow surface, intake, water channel or other water passage surfaces, firstly chip away the loose material in honey b artificially or by pneumatic pick, wash the surface by high pressure water, dry the surface, and then use epo*y mortar which is one grade highe

11、r than original concrete to repair the defect in the sequence of leveling , paction and troweling. Pitted SurfaceIf pittedsurfaceoccurreson the surface with structure requirement or water passage surface, grinding machine shall be used for polishing and leveling the pitted surface. The surface shall

12、 be washed by high pressure water. If only requirement, mortar which is one grade higher than original concrete shall be used for repairing the defect in the sequence of leveling, paction and troweling. Cavity To chipaway the loose aggregate in the cavity until the pleted and pacted concrete surface

13、 be e*posed. Inverted trapezoidal shape is most proper for chipping shape (The chipping line is better perpendicular to facade of the surface or counter-slope with the included angle in the range of 4590 is most proper. Circular arc-shape chipping shall be avoided. Consequent-slope with an included

14、angle between chipping line and surface more than 90shall be avoided, because the filling material is hard to sticking under such condition). Then, wash the regular chipping surface by high-pressure water. Fine aggregate concrete one grade higher than original concrete shall be filled into the chipp

15、ing area followedby paction, leveling.Local Depression and GrooveFirst of all, remove loose materials within the groove and the depth of chipping shall be according with the thickness of steel bar cover (mostly 3-5cm). The shape of chipping is preferred to be inverted trapezoidal (The chipping line

16、is better perpendicular to facade of the surface or counter-slope with the included angle in the range of 4590 is most proper. Circular arc-shape chipping shall be avoided. Consequent-slope with an included angle between chipping line and surface more than 90 shall be avoided, because the filling ma

17、terial is hard to sticking under such condition).Then wash the regular groove with high pressure water and backfill the groove with mortar that is one grade higher than original concrete followed by paction, leveling and troweling.Reinforcement E*posureRemove the concrete around e*posed steel bar wi

18、thin 3-5cm (including the surface of steel) and the depth of chipping shall be according with the thickness of steel bar cover (mostly 3-5cm). The shape of chipping is preferred to be inverted trapezoidal (The chipping line is better perpendicular to facade of the surface or counter-slope with the i

19、ncluded angle in the range of 4590 is most proper. Circular arc-shape chipping shall be avoided. Consequent-slope with an included angle between chipping line and surface more than 90 shall be avoided to make sure the filling material is easy to sticking, shaping regular groove and the steel fully e

20、*posed). Then wash the groove and steel with high pressure water and backfill the fine concrete or mortar that is one grader higher than original concrete in the sequence of paction, leveling and troweling. Crack and Cold joint Concrete crack, according to their occurrence, is divided into surface c

21、rack、deep crack、penetrating crack. As to the surface crack, mostly there is no need to repair. Only when it occurs in the position which is required for the structure、overflowing and anti-seepage, the surface crack shall be sealed with cement mortar or epo*y mortar. The other cracks shall be dealt w

22、ith through different methods on the basis of their location and width. 1) As to the crack and cold joint, if there is no requirement for the structure, overflowing and anti-seepage and the width of crack is not more than 1mm, it will not be repaired. And if the width of crack is more than 1mm, it s

23、hall be repaired through chipping the crack to bee a trapezoidal trench (width 50mm and depth 30-40mm). Then wash the surface by high pressure water and backfill the trapezoidal trench with micro-e*panding mortar in the sequence of paction, leveling and troweling.2) Upstream Split Crack: As for the

24、upstream split crack, it shall be disposed by chipping the crack to be a trapezoidal trench (width 100mm and depth 50-70mm), and wash the surface with high pressure water, dry the surface with fire, then paint epo*y resin and backfill the trapezoidal trench with epo*y mortar in time followed by paction, leveling and troweling.3) Surfacecrackofconcrete：Steel rebarspanning the crack willbeused to prevent development of the cracks, and the distribution of the steel bars will be decided by the employers and cont