Field Testing of Reinforced Concrete Structures (with references to International Standards)

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Field Testing of Reinforced Concrete
Structures(with references to International
Standards)

• F.Papworth

Historical
Buildings
Industrial
Mines
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Expected Outcomes Site Surveys

• Understand what sort of job you can do yourself
  with minimal risk
• Understand what sort of information can be
  obtained
• Understand when you should get help
• Have a little background in the common tests
• You may be able to use with minimal training
• Testing companies may use on site

Lets take a closer look at this
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Buried Defects Impact Echo Pulse
Echo Thermography Radar Nuclear
Cover Quality Sorptivity Air Permeability Water
Permeability
Corrosion Testing Potentials Resistivity Polaris
ation Resistance Embedded Half Cell Carbonation
Depth Chloride Penetration
Embedment Cable Tension Bolt Pull Out Cover
Coatings Peel Tester Pull off Thickness
Visual Inspection Magnifier Gauge Deformation Moni
tor Strain Camera
Surface Flatness/Levelness Abrasion
Resistance Dusting
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Corrosion Reaction
Water
Chloride
Oxygen
O2
H2O
Fe2O3H2O (Rust)
Secondary Reaction
2Fe(OH)2
H2O
O2
4(OH)-
Cathodic Reaction
Anodic Reaction
Current
Electrolyte
2Fe
4e-
4e- Electron Transfer
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Strength Assessment Early Age

• Why Early Age Assessment
• Check before lifting/stripping
• Check before applying prestress
• Check to stop curing
• Water retaining code 75 fc
• Bridges Code 60 60 fc
• Schmidt Hammer Method
• Repetitive so establish conversion curve
• Accurate to 10-15
• If 8MPa required lift safe to lift at 10MPa
• Surface strength only
• Maturity Measurement Method
• Doubles as temperature measurement

Cylinder strengths underestimate insitu strength
7 or 14 day specs overstate requirements
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Strength Assessment

• Check Old Structures
• Check capacity for increased load
• Floor slabs when changing usage
• Buildings where heavy equipment to be located
• Bridges for increased capacity
• Check continued capacity of historic structures
• Where no design information available
• Check for progressive weakening
• Leaching of water retaining structures
• Schmidt Rebound
• No conversion curves available
• Surface hardening due to carbonation
• 25 with carbonation allowance, 50 no
  carbonation allowance

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Strength Assessment

• Rebound Hammer
• Ultrasonics
• Maturity
• Pull off tests