CT 523 - Flexural Strength Flashcards
(26 cards)
What type of loading is done to complete this test? 1st point loading, 2nd point loading, 3rd point loading
3rd point loading
To what accuracy must the testing machine be accurate to of the maximum load?
1% accuracy
When must the test machine be verified or calibrated? 5 part answer
- Within 13 months of last verification, 2. On original installation, 3. After relocation, 4. After making repairs or adjustments that affect the operation of the force being applied, 5. Whenever there is reason to suspect the accuracy of the indicated forces.
The flexural testing apparatus shall be capable of maintaining the span length and distance between the lines of loading within how much?
+- 0.05”
The ratio of the horizontal distance between the line of application of the force and the line of the nearest reaction to the depth of beam shall be?
1.0 +- 0.03
Loading blocks and support blocks shall not be more than ______ high.
2.50”
Each block surface in contact with the specimen shall not depart from a plane by more than ___________.
0.002”
Support blocks shall be _______ to _________.
Free to rotate.
All surfaces shall be __________ and _______ of scars, indentation, holes, or inscribed identification marks.
Smooth and free
The smaller cross sectional dimension of the beam is at least __________ times the nominal maximum size of the coarse aggregate.
Three
What is the permissible tolerance in hours of when the specimen should be tested for 28 Day test age?
+- 20 hours
What range of force is the specimen brought to for checking gaps with a feeler gage?
3-6% of ultimate force
What feeler gage range is used to determine if shims should be used? Over how wide?
0.004” - 0.015”, 1”
What are the dimensions of leather shims?
0.25” thick, 1-2” wide, and full width of specimen
Is grinding allowed instead of shims?
Yes
Is capping allowed to get rid of gaps?
Yes
What range of psi/min should the specimen be loaded to?
125-175 psi/min
What rate range in lbs/min should a 6”x6”x18” specimen be loaded to?
1500-2100 lb/min
When should the six measurements be taken of the specimen and where?
After rupture and of the fracture face
Where should the six measurements be taken?
3 for width, one at each edge with one in the middle, 3 for depth, one at each edge and one in the middle
What should be done with the 3 measurements of taken from each depth and width?
Averaged
What should be fractured face measurements be rounded to?
0.05”
If the fracture occurs in the tension surface outside of the middle third of the span length by not more than ___% of the span length
5%
Identify each of the formulas below:
R=PL/bd^2 R=3Pa/bd^2
R=PL/bd^2 is used for middle third rupture and R=3Pa/bd^2 is used for rupture outside of the middle third but within 5% of length.
