18 Questions
What is the criterion of quality concrete in structural member design?
Compressive strength
At what age are concrete specimens typically tested to determine compressive strength?
28 days
In what modes can the failure of concrete occur during compressive strength testing?
Shear and splitting failure
What is the specified minimum value for the compressive strength of concrete according to NSCP 2015 Section 401.2.2?
17 MPa
What is the type of loading condition used when testing 28-day-old concrete cylinders for compressive strength?
Static load
What is the relationship that influences the performance of a reinforced concrete member under load?
Stress-strain relationship of concrete and steel
What is the compressive strength range of normal weight concrete at about 28 days?
10 MPa to 40 MPa
What are the disadvantages of lightweight structural concretes?
Higher cost, more care in placing, greater porosity, and more drying shrinkage
What is the main reason for using lightweight concrete?
To reduce dead load
What type of concrete is typically used in radiation shields and counterweights?
Heavyweight concrete
Which type of specimen shape leads to lower compressive strength values?
6in x 12in cylinders
At what age does the development of strength start for normal weight concrete?
7 days
What factor can increase the strength of concrete?
Increasing the cement content
How do special admixtures affect concrete?
Improve quality and strength
What effect does using a vibrator have on concrete?
Lessens the percentage of air voids
How does the curing time influence the strength of concrete?
The longer the curing time, the greater the strength
When is concrete typically tested for strength?
At 28 days
What happens to the compressive strength of concrete under sustained loads?
Reduces by 30%
Test your knowledge on the properties, proportions, and mixing methods of concrete constituents. Learn about the impact of cement content, aggregates, and admixtures on the strength and quality of concrete.
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