Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
49 Cards in this Set
- Front
- Back
What is used to measure the consistency of concrete |
Slump Test |
|
Air Entrainment concrete quality |
Resistance to freeze/thaw cycles |
|
Concrete will reach approximately ___ - ___ % after 7 days |
60 - 70% |
|
Type I Portland Cement |
Normal, used for most work |
|
Type II Portland Cement |
Moderate Sulfate Resistance |
|
Type III Portland Cement |
High Early Strenght |
|
Type IV Portland Cement |
Low Heat of Hydration |
|
Type V Portland Cement |
High Sulfate Resistance |
|
If the water cement ratio is high, the concrete will be |
Not as strong |
|
Affect of a retarder in concrete |
Slows down hydration time and extends the setting time |
|
Affect of an accelerator |
Speed up the hydration time, makes it set faster |
|
Most efficient Accelerator (also cheapest) |
Calcium Chloride |
|
Slump should range from |
3-4" |
|
Delivery time for Ready Mix Concrete |
90 minutes, or 300 revolutions |
|
Best foundations to use in poor soils |
Piles & Drilled Peers (Augered Piers) |
|
Most effective way to compact granular soils |
Vibration |
|
What type of footing is best for columns |
Isolated |
|
Best type of foundation when the bearing capacity of the soil is low |
Floating Foundation |
|
What must be concerns of concrete form designers |
- Weight - Shape - Load |
|
Concrete is approximately ____ pcf. |
150 |
|
What are used to insure that the form does not stick ot the concrete |
Form release agent |
|
Splices in rebar should not be less than ____" |
12" |
|
Contraction Joint (Control Joint) |
Accommodate movement |
|
Isolation Joint (Expansion Joint) |
Used as points of restraint between elements of a structure |
|
Construction Joints |
Joints introduced for convenience or need of the construction process
|
|
Control joints are cut to ___ thickness of the slab |
1/4 |
|
What type of aggregates are preferred for pump mix concrete |
Rounded Aggregates (river gravel) |
|
What intervals should a vibrator be inserted into concrete |
15" |
|
How long should vibrator be inserted into concrete |
10-15 seconds |
|
Concrete is _________ by vibrating air bubbles to the surface |
Consolidated |
|
The proper vibrator technique is _____ insertion and _____ withdrawl |
- Fast - Slow |
|
Excessive Vibration causes |
Segregation |
|
Hot weather can have what affect on concrete |
Less strength |
|
Concrete should ______ be placed on frozen subgrade |
Never |
|
Concrete _______ causes the concrete to dry at the proper rate |
Curing |
|
How much should concrete be Air-Entrained to avoid scaling |
5-8% |
|
What is a method to control scaling |
Air Entrain |
|
Max slump for lightweight concrete |
5" |
|
What can be added to make concrete flow better |
Plasticizer |
|
A plasticizer can sometimes cause _____ in concrete |
Segregation |
|
Chemical reaction between water and concrete is called |
Hydration |
|
Recommended slump for piers |
1-3" |
|
Increase in strength of concrete stops ____ |
when there is no moisture present |
|
______ is a way to obtain a non-slip finish on unhardened concrete surfaces |
Brooming |
|
The maximum temp for placing concrete is |
90 degrees |
|
Type of joint that permits both vertical and horizontal movement |
Isolation Joint |
|
The design element in a form that allows for settlement and deflection is a ______ |
camber |
|
Within how man hours after concrete is placed on a jobsite should concrete joints be sawn |
4 - 12 hours |
|
Air Entraining concrete will not |
Increase the water tightness |