REPAIR MANUAL Dr. Mohammed Maslehuddin Research Institute King Fahd University of Petroleum and Minerals

Purpose of the Manual Assist engineers in diagnosing concrete deterioration problems and planning repair and rehabilitation of deteriorating structures.

Contents of Repair Manual Chapter 1: Guide to mechanisms of concrete deterioration Chapter 2: Assessment of the extent of concrete deterioration Chapter 3: Strategy for repair of deteriorated concrete structures Chapter 4: Repair materials and their evaluation

Contents (contd.) Chapter 5: Repair procedures Chapter 6: Repair systems Chapter 7: Long-term monitoring strategies

Chapter 1 A guide to forms of concrete deterioration Reinforcement corrosion Carbonation Sulfate attack Salt weathering Alkali-aggregate reactivity Cracking of concrete Acid attack Damage due to fire Attack due to micro-organisms

Chapter 2 Assessment of Concrete Deterioration Preparation (preparatory desk work) Preliminary investigation (visual inspection and appraisal) Detailed investigation (data collection, field measurements, condition survey, sample collection, testing of samples, analysis and evaluation) Conclusion and recommendations

Chapter 2 (contd.) Preparation prior to inspection Design information Plans/drawings, as-built drawings, specifications and other related information Location of the structure and topology and accessibility Structural drawings for reinforcement details Service history

Chapter 2 (contd.) Preliminary investigation Structural condition, extent of cracking, damage Safety of the structure Need for commissioning a detailed inspection Accessories needed for detailed inspection Traffic control requirements Any unusual problems facing the structure

Chapter 2 (contd.) Detailed investigation Data collection Field measurements and condition survey Sample collection Testing and field samples Analysis and evaluation Report Conclusions Recommendations

Chapter 2 (contd.) Commonly used test methods Methods for estimating in-situ concrete strength Methods for determining properties other than strength Methods for the physical evaluation of structures

Chapter 3 Strategy for repair of deteriorated concrete structures Cause and extent of damage Consequence of the damage Time for intervention Economics Operational constraints

Chapter 3 Repair options No repair Repair Cosmetic Partial Total Partial repair or total replacement

Factors influencing the selection of repair strategy (No repair) Minimal damage No chance of re-occurrence of damage due to overload etc. Expected service life is more than the design life Appearance is not a problem

Factors influencing the selection of repair strategy (Repair) Cosmetic repair Limited deterioration Rate of deterioration is too low as in the no repair option Improve the appearance

Factors influencing the selection of repair strategy (Repair) Partial repair (patch repair) Rectify apparent defects Structural safety is not affected

Factors influencing the selection of repair strategy (Repair) Total repair Advanced deterioration Structurally unsafe Operational constraints for total replacement

Factors influencing the selection of repair strategy for corrosion (No repair) Active corrosion but corrosion rate is low Low chloride concentration Structural integrity is not compromised

Factors influencing the selection of repair strategy for corrosion (Repair) Cosmetic repair Active corrosion but corrosion rate is low Chloride concentration is high No spalling, localized delamination Structural integrity is not affected

Partial repair (patch repair) Factors influencing the selection of repair strategy for corrosion (Repair) Partial repair (patch repair) Active corrosion Localized delamination or spalling Structural safety is not affected

Factors influencing the selection of repair strategy for corrosion (Repair) Total repair Active corrosion Uniform spalling or delamination Excessive loss of cross section of bars at many locations

Factors influencing the selection of repair strategy for corrosion (Partial or total replacement) Repair is economically not feasible No operational constraints Structure is structurally unsound

Chapter 4 Repair Materials and their Evaluation Repair mortars Cementitious repair mortars Polymer modified cementitious mortars Resin-based repair mortars Sprayed concrete Injection grout Flowing micro concrete Bond coat materials Steel primers Surface coatings

Chapter 4 Repair Materials and their Evaluation Test methods Compliance criteria

Chapter 5 Repair Procedures Repair of cracked and deteriorated concrete Shrinkage cracks Settlement cracks Thermal cracks Dormant or dead cracks Live cracks

Chapter 5 Repair Procedures (contd.) Vacuum impregnation Resin injection Repair of surface defects Repair of inadequate cover Repair of deteriorated and cracked concrete due to sulfate attack and salt scaling Repair of cracks caused by alkali-silica reaction Repair of deterioration due to exposure to chemicals Repair of deterioration and cracking due to exposure to high temperature and fire Repair of spalled concrete

Chapter 6 Repair systems Marine environments System 7 or 1 Below ground structures System 1 or 6 Sulfur fumes System 6, 5 or 8 Acid exposure System 6, 5 or Sweet or saline water System 9 or 10 Fire damage System 7 or 8

Chapter 7 Long-term Monitoring Strategies Visual inspection Debonding Monitoring chloride and moisture content Measurement of carbonation depth Assessing reinforcement corrosion Resistivity Corrosion potentials Corrosion rate