Slump
What is the purpose of the slump test?
Measure / gauge workability of concrete sample.
- 16" to 24"
- 5/8" diameter
- Semi-hemispherical tip
What type of alcohol is used in this test (typically outside of lab)?
70% Isopropyl Alcohol
What should be done if the concrete contains agg. larger than is appropriate for the size of the molds being used?
Wet Sieving (Screening)
What type of strength does cylinders measure? What about beams?
Cylinders = compressive strength
Beams = flexural strength
What are the dimensions of the slump cone?
What are the valves on the side of the air meter called, where water is added during the test?
Petcock!
What is this test method required for?
Lightweight concrete mixtures!
What must occur before a sample of concrete can be taken from a revolving drum mixer?
All water and admixtures must be added to the mixer!
What are the 4 standard sizes of cylinder molds?
2x4, 3x6, 4x8 and 6x12 (all in inches)
How many times do you hit the cone with the mallet after rodding each layer?
NONE!!! PLEASE DO NOT TAP THE MALLET ON THIS TEST!!!
How much should you overfill the bowl by when filling the final layer?
1/8" above the bowl before striking off
What are the minimum dimensions of the strike off bar?
3/4" x 1/8" x 12"
What action is required after the individual concrete samples have been transported to the place where tests are to be performed?
Combine and remix the samples with a shovel!
What is the maximum aggregate size allowed for these tests?
2 in.
You lift the slump cone and your concrete member falls over to one side; what should you do as a student performing the test?
The test is a shear result, and thus is invalid! You should inform the examiner and let them know why the test is an invalid result.
How often should the air meter equipment be calibrated?
Every 3 months! (Allegedly...)
You finish the test and discharge of the sample from the pot. The examiner checks the pot and there is residue stuck to the bottom of the pot. What should you do?
Hopefully y'all have a chill examiner, and you won't have to repeat the test :)
Describe the procedure for collecting a sample from a paving mixer. (HINT: 2 steps)
- Discharge the contents of the paving mixer
- Obtain samples from at least five different portions of the pile
I have a slump of 1 in. for my concrete sample... can I rod my sample, or do I need to vibrate it only?
You can choose to rod OR vibrate the sample!
You are filling the final layer of the slump cone, and you overfill the top of the cone. After performing 7 rods, the concrete has dropped underneath the top of the cone. What are your next steps?
- Place more concrete on top of the cone
- Finish rodding the 25 (18 additional rods ONLY)
- Use the rod to clear all excess concrete from the top of the cone
What can occur if the concrete sample in the bowl is vibrated for too long? (HINT: one word I am looking for...)
Frothing!!!
What should you do if more than 2.5 pints of isopropyl alcohol are added to the test?
Start molding specimens for strength tests within how many minutes after fabricating the composite sample?
15 min
How many rods should a standard beam get per layer??? (what number is it exactly)
63 rods per layer (how do we find this?)