Maricopa Community Colleges  CON207   20052-20086 
Official Course Description: MCCCD Approval: 07/22/08
CON207 20052-20086 LEC 1 Credit(s) 1 Period(s)
Repairing Concrete
Repairing cavities, using shotcrete and raising settled slabs. Repairing structural concrete with "preplaced aggregate". Use of protective and decorative coatings and selecting optimum repair materials. Crack repair and cathodic protection methods for preventing corrosion in reinforcing steel.
Prerequisites: (Registered apprentice status and CON206) or permission of the apprenticeship coordinator.
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MCCCD Official Course Competencies:
 
CON207   20052-20086 Repairing Concrete
1. Describe specific procedural steps which are applicable to all concrete cavity repairs. (I)
2. Describe specific procedures for repairing concrete surfaces with shotcrete. (II)
3. Describe procedures for raising settled slabs by slabjacking. (III)
4. Explain how the "preplaced aggregate" method is used to repair structural concrete. (IV)
5. List specific types of protective and decorative coatings and explain the capabilities and limitations of each. (V)
6. Explain specific factors that must be considered when selecting repair materials for concrete. (VI)
7. Describe specific methods for repairing cracks in concrete. (VII)
8. Explain the principle behind cathodic protection of reinforcing steel and describe specific installation methods. (VIII)
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MCCCD Official Course Outline:
 
CON207   20052-20086 Repairing Concrete
    I. Basic Repair Procedures
        A. Preparation
          1. Remove all unsound material
          2. Shape cavity
        B. Placing patching material
          1. Clean cavity
          2. Wet cavity faces
          3. Apply bond coat (if dry pack)
        C. Repair material
          1. Dry pack
          2. Plastic mortar
        D. Curing - wet
      II. Shotcrete
          A. Mixture
            1. Dry-mix
            2. Wet-mix
          B. Rebound
          C. Bond
          D. Surface preparation
            1. Remove unsound material
            2. Place/replace reinforcement
            3. Wet as required
          E. Placement
          F. Finishing
          G. Curing
          H. Quality control
        III. Slabjacking
            A. Mixing grout
            B. Equipment
              1. Rock drill
              2. Grout mixer
              3. Grout pump
            C. Repair procedure
              1. Locate and drill holes
              2. Pump grout
              3. Patch holes
          IV. Preplaced Aggregate
              A. Mixing
              B. Selecting aggregate
                1. Minimum size
                2. Maximum size
              C. Choosing grout
              D. Preparing the surface
                1. Removing old concrete
                2. Sloping upper edges
                3. Replacing/adding reinforcement
              E. Preparing forms
              F. Placing the aggregates
              G. Saturating the aggregates
              H. Batching and checking grout
              I. Pumping the grout
                1. Vertical pipes
                2. Nippled forms
            V. Protective and Decorative Coatings
                A. Water-based portland cement paints
                  1. Capabilities
                  2. Limitations
                B. Oil-free urethanes
                  1. Capabilities
                  2. Limitations
                C. Acrylics
                  1. Capabilities
                  2. Limitations
                D. Catalyzed epoxies
                  1. Capabilities
                  2. Limitations
                E. Latex emulsions
                  1. Capabilities
                  2. Limitations
                F. Alkyds
                  1. Capabilities
                  2. Limitations
                G. Two-component urethanes
                  1. Capabilities
                  2. Limitations
                H. Epoxy esters
                  1. Capabilities
                  2. Limitations
                I. Vinyls
                  1. Capabilities
                  2. Limitations
                J. Phenolics
                  1. Capabilities
                  2. Limitations
              VI. Selecting Repair Materials
                  A. Dimensional stability
                  B. Coefficient of thermal expansion
                  C. Elasticity
                  D. Permeability
                VII. Crack Repair
                    A. Epoxy injection
                      1. Clean cracks
                      2. Seal surfaces
                      3. Install entry ports
                      4. Mix epoxy
                      5. Inject epoxy
                      6. Remove surface seal
                    B. Routing and sealing
                      1. Clean
                      2. Route
                      3. Seal
                    C. Stitching
                      1. Drill
                      2. Install "stitching dogs"
                    D. Adding reinforcement
                      1. Conventional reinforcement
                      2. External prestressing
                    E. Drilling and plugging
                    F. Flexible sealing
                    G. Portland cement or chemical grouting
                    H. Drypack mortar
                    I. Polymer impregnation
                    J. Overlays
                    K. Surface treatments
                  VIII. Cathodic Protection
                      A. Rebar corrosion
                      B. Principle of cathodic protection
                      C. Installation methods
                        1. Platinum wire and carbon fiber
                        2. Conductive polymer
                        3. Low voltage direct current
                      D. Cost
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