1. CONCRETE TESTING
Dr. Sophia Hassiotis

2. In This Presentation Strength Testing Durability Testing
Compressive Testing
Tensile Testing
Beam
Split Cylinder
Durability Testing
Chemical Attack
Freeze-Thaw

3. Strength Concrete is most often known for its compressive strength
Flexural strength is of importance when used in rigid pavements.
Most often, 28-day strength is specified although other strengths such as 1-day, 7-day, 56-day and 90-day strength can be used as well.
Concrete continues to gain strength over time
Curing methods can pay a major
role in Concrete strength gain and
a standard curing method has to be
observed for repeatable test results.  

4. Compressive Strength
Compressive Strength of Cylindrical Concrete Specimens (ASTM C39)
Apparatus: Forney Hydraulic Universal Testing Machine
200,000 lbs Tension,
400,000 lbs Compression
Accuracy is approximately 10% of the maximum load.

5. Compressive Strength — Testing Procedure
Maintain the specimen in a water storage tanks and controlled temperature of °F [ °C] up to the time of compression testing.

6. Testing Procedure (cont)
Carefully align the axis of the specimen with the center of thrust of the spherically seated upper platen.
Bring the upper platen to
bear on the specimen, adjusting
the load to obtain uniform
seating of the specimen, no more
than 50% of the ultimate load.
Center the specimen on the
lower platen of the testing machine.

7. Testing Procedure (cont)
Apply the load at a loading rate of 35 psi/s (within a range of 28 to 42 psi/s). Maintain this loading rate at least for the last half of the anticipated loading phase.
Make no adjustment in the rate of movement till the end of the test
Apply the compressive load until the load indicator shows that the load is decreasing steadily and the specimen displays a well-defined cracking pattern. Record the maximum load (lb)

8. Types of Concrete Fracture (ASTM C 39)

9. Tensile Strength
Concrete is not nearly as strong in tension as it is in compression.
Concrete flexural strength is important in some applications. For example, flexural strength is typically used as a Concrete performance measure for pavements because it best simulates flexural stresses at the bottom of the Concrete surface course as it is subjected to loading.

10. Tensile Strength Testing — Flexural strength
The standard flexural strength test is:
AASHTO T 97 and ASTM C 78: Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)
AASHTO T 177 and ASTM C 293: Flexural Strength of Concrete (Using Simple Beam with Center-Point Loading)  

11. Tensile Strength Tesing — Split Tension Test
The standard split tension test is:
AASHTO T 198 and ASTM C 496: Splitting Tensile Strength of
Cylindrical Concrete Specimens

12. Compressive to Tensile Strength Relationships
In absence of flexural or tensile testing,
the ACI Concrete Code gives some rough rules-of-thumb
for converting compressive strength:

13. Durability of Concrete
Durability is a measure of how Concrete performs over time. 
Two major factors that affect Concrete durability are freeze-thaw cycles and chemical attack. 

14. Durability Testing —Chemical Attack
Some standard tests for chemical attack are:
AASHTO T 259: Resistance of Concrete to Chloride Ion Penetration
AASHTO T 277 and ASTM C 1202: Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration
AASHTO T 303 and ASTM C 227: Accelerated Detection of Potentially Deleterious Expansion of Mortar Bars Due to Alkali-Silica Reaction  

15. Durability Testing — Freeze/Thaw
Standard freeze-thaw tests are:
AASHTO T 161 and ASTM C 666: Resistance of Concrete to Rapid Freezing and Thawing
AASHTO T 121: Mass Per Cubic Meter (Cubic Foot), Yield, and Air Content (Gravimetric) of Concrete
ASTM C 671: Critical Dilation of Concrete Specimens Subjected to Freezing

16. LAB REPORT
Each one of you will write and submit his/her own lab report (no group reports)
Your lab report should be typed and all figures should be professional looking. A big percentage of your grade will be dedicated to the degree of professionalism of your report.
DUE: One week after cylinder breaking
Report the following information:
Cover page with Name, Lab group, Group members, Date
Calculations for concrete mixing,
Procedure for mixing concrete in the lab. ASTM test number
Procedure for Slump Testing, ASTM test number
Procedure for setting cylinders, size of cylinders, ASTM test number
When do you remove the cylinders, how do you cure and for how long
Compression testing. Record testing machine and procedure for compression testing
Record Compressive strength ,type of fracture, Defects in specimen and,
Age of specimen.

17. Example of Report (2013)