Flashcards in Concrete Deck (45)
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1
Concrete
Aggregate, Cement, Water, and Admixture
2
Portland Cement
Lime, Silica, Alumina, Gypsum
3
How long does Cement take to reach full strength?
28 Days
4
Isolation (expansion) Joint
Provide for lateral movement between slabs. Extend the full depth of the Concrete
5
Concrete Qualities
Strength, Durability, Stability, Availability, Adaptability, and Low-cost
6
Properties of Concrete
Constituents, Skills used in placing
7
Concrete resistance to freeze/thaw and deicing chemicals
Apply admixtures
8
Concrete resistance to abrasion and wear
Increased if the concrete mix contains well-graded strong aggregate
9
Methods of Concrete Placement
Cast in Place, Sprayed, Mixed in Place
10
Process of Hydration
Cement and Water mixture results in hardening
11
Types of Aggregate for Concrete
Sand, Gravel, Crushed Stone
12
Selection of Aggregate for Concrete
Resistance to abrasion, Performance, Resistance to effects of freezing/chemicals, Range of Aggregates
13
Admixtures
Workability, Reduce Moisture, Increase durability, Resistance to Freezing, Accelerate or retard hardening or setting, Increase Flowability
14
Water Quality for Concrete
Potable Water (Uncontaminated)
15
2 Styles of Mixing Concrete
Ready-mix and On-site Mixing
16
Slump Test
Determines Relative Consistency & Reflects changes in the amount of water in the mix
17
Air Content Test
Determines the air entertainment at the time of use
18
Cylinder Test
Determines the compressive strength of cured concrete
19
Site Preparation for Use of Concrete
Granular sub-base over-prepared, and compacted, subgrade
20
Benefits of Reinforcement
Controls cracking and give greater tensile strength
21
Purpose of Joints
Minimize damaging effects of expansion and contraction in concrete due to temperature variations and the presence of moisture
22
Control, or contraction, joints
Designed to restrict the cracking of concrete at predetermined locations. ¼ to ⅓ the thickness of the concrete. At intervals roughly the width of slab
23
Construction Joint
Provide places where the casting of concrete can be stopped
24
Joint Fillers
Joints tend to be filled and sealed to keep out moisture and debris
25
Types of Joint Fillers
Fiber Filler
Wood Dividers
Plastics, rubber, cork, or metal
26
Joint Sealant
Prevents filler material from bleeding or being squeezed up. Keep out debris. Keep out water
27
Two of the most common types of concrete finishes
Floating and Troweling
28
Colored Concrete One Course Method
Mixing pigments when concrete is created
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Colored Concrete Two-Course Method
Top or finish surface after laying regular concrete
30
Dry-shake Method
Sprinkling Special pigments on the surface
31
Stains and Paints
Typically done on existing concrete
32
Exposed Aggregate
Resistance to slipping and heavy wear
33
One-course Aggregate Finish
Fine aggregate added to the concrete mix. Hosing or acid washing and brushing
Surface retardant applied
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Two-course Aggregate Finish
Base concrete laid. Concrete topping with aggregate added over base concrete Hosing or acid washing and brushing
35
Seeding Aggregate Finish
Sprinkling aggregate over a freshly placed concrete base
36
Special Non-slip finishes
Floats, trowels, brooms, or dry-shaking grains onto the surface. Grains such as Silicon carbide and aluminum oxide
37
Edging
Prevents chipping
Helps compact and harden
38
Wet Covering
Covering with moisture-retaining fabric
Keeps concrete wet
39
Waterproof paper or plastic sheets
Prevents rapid loss of moisture from the concrete
40
Sprinkling or ponding of water
Effective but expensive
Sand or earth berms to be removed later
41
Curing compounds
Used in conjunction with coverings. Used to help sustain curing
42
Temperature Control
Cover with sheets. Use Heaters
43
Sealers and Glaziers
Prevent or Reduce Moisture Penetration and Chloride Penetration
44
Sealers and Glaziers
Used to waterproof or bring out the natural color
45
