BCN 5905

1
BCN 5905

• Chapter 16
• Control Tests for Concrete

2
General Info

• Specifiers moving to performance based specs
  (strength and durability).
• Final performance of the concrete be achieved
  regardless of how you do it.
• Physical tests and concrete properties are used
  to measure acceptance (slump and air content)
• Most specs today are still a combination of
  prescriptive and performance requirements.

3
Classes of Tests

• Testing individual components of the mix
  (aggregates and cement for mix design)
• Testing the fresh and hardened concrete for
  acceptance
• Testing Organizations - Standards
• ASTM (American Society for Testing and Materials)
• AASHTO (American Association of State Highway and
  Transportation Officials)

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Frequency of Testing

• Aggregate moisture tests - 2 x per day
• 1 change in moisture content of FA 13 pcy of
  water
• Slump tests and air content for each sample of
  concrete from which cylinders are made.
• Strength testing (cylinders) should be made
• not less than once per day nor less than once per
  150 cy of concrete
• Nor less than once per 5000 sq.ft. of surface
  area for slabs or walls each day

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Cont

• Samples should be lab cured when tested for
  acceptance or performance
• Samples should be field cured to determine the
  in-place compressive strength of the concrete
• One 7-day and Two 28-day cylinders are tested per
  batch.

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Testing Aggregates

• Sampling (ASTM D75)
• Coarse aggregate
• Quartering method
• Fine Aggregate
• Sample splitter
• Grading (ASTM C136)
• Sieve Analysis
• Moisture Content(ASTM 566)
• Oven dry, Microwave, Hotplate, Moisture meters

7
Testing Fresh Concrete

• Sampling (ASTM C172) - 1 cu.ft.
• Consistency (ASTM C143) - slump
• complete test in 2-1/2 minutes
• K-Slump Tester
• Kelly Ball
• Vebe
• Temperature Measurement (ASTM C1064)
• Take test within 5-minutes after sample obtained

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Cont

• Density and Yield (ASTM C138)
• Unit Weight
• Yield (wt. of ingredients/unit wt.)
• Air Content
• Volumetric Method (ASTM C173)
• Pressure Method (ASTM 231)
• Boyles Law

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Strength Specimens ASTM C31

• 6 x 12-inch cylinders
• rigid and plastic molds
• filled in 3-layers
• 4 x 8-inch cylinders
• 3/4-inch max.
• filled in 3-layers
• 6 x 6 x 24 to 36-inch forms
• filled in 2-layers
• vibration

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Time of Setting ASTM C403

• Initial Set
• penetration resistance of 500 psi
• 2-6 hours after batching
• Final Set
• penetration resistance of 4000 psi
• 4-12 hours after batching

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Testing Hardened Concrete

• Cured specimens molded according to ASTM C31
• In-situ specimens cored from hardened concrete
  according to ASTM C42
• Specimens made from cast-in-place cylinder molds
  according to ASTM C873
• In-place CS of concrete (Fig. 16-13)
• Length-to-Diameter of 21

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Strength Tests of Hardened Concrete

• Compressive Strength Testing of Concrete, ASTM
  C39 See next slide
• Unbonded neoprene caps, ASTM C1231
• Flexural Strength - 3rd Point Method, ASTM C78
• Flexural Strength - Center Point Loading, ASTM
  C293
• fr 7.5(fc)1/2
• Splitting Tensile Strength of Concrete. ASTM C496

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Failure Modes of Compression Testing
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Flexure Strength Testing - Third Point Loading
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Flexure Strength Testing - Center Point Loading
P
depth
L span
16
Splitting Tensile Test
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Air Content

• Petrographic Determination ofAir-Void System,
  ASTM C457
• hardened concrete air-void system
• void size and air-void distribution system
• freeze/thaw durability

18
Density(Gs), Absorption and Voids

• ASTM C642
• Density or Unit Weight of Hardened Concrete
• Absorption of Hardened Concrete
• Volume of Voids in Hardened Concrete
• Density of Hardened Concrete by Nuclear Density
  Gage

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Other Tests

• Determination of Chloride Ion Content in Hardened
  Concrete
• ASTM C1152
• ASTM C1218
• Volume and Length Change
• Shrinkage of Hardened Concrete
• ASTM C157

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Durability

• Frost Resistance
• ASTM C666
• Freezing in air and thawing in water
• Freezing in water and thawing in water
• Dynamic modulus of elasticity
• Sulfate Resistance
• ASTM C1012
• Corrosion Resistance
• ASTM C876 - Potentiometric Mapping

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Corrosion Determination - Potentiometric Mapping
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Cont

• Abrasion Resistance
• ASTM C779
• ASTM C944
• ASTM C1138 (underwater test)
• Carbonation
• Phenolphthalein indicator method
• Permeability
• ASTM C1202 Rapid Chloride Permeability Test

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Nondestructive Test Methods

• Rebound Hammer Tests
• Schmidt Hammer

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http//www.corvib.com/concrete/schmidt.htm
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NDT

• Penetration Testing - Windsor Probe
• Maturity Testing
• In-place Compressive Strength
• Pullout Tests
• In-place Shear Strength

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NDT

• Ultrasonic Pulse Velocity
• Dynamic modulus of elasticity
• Cracking

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Pulse Velocity Testing
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NDT

• Other Dynamic Tests
• Impact echo

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Impact Echo Testing