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7/31/2019 Fundamentals of Concrete 2010
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Fundamentals of Concrete
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There is No such Animal as aCement @$&!*^#%
Composition of Concrete
PC + Water + Aggregates (FA & CA) + Voids
Properties of Fresh Concrete and HardenedConcrete
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Fresh Properties - ASTM
Slump
Temperature
Density & Yield Air Content
Time of Setting
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Hardened Properties - ASTM
Strength
Air Content
Density, Absorption and Voids Volume Change
Durability
Permeability
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Strength
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Durability
Freeze Thaw
Chloride-Ion
Alkali-Aggregate Sulfate
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How does Concrete Get ItsStrength
PC + water = hydration reaction > GLUE +Heat
Cementitious material literally glues all of theinert (non-reactive) aggregates together toproduce a solid load bearing mass that wecall PCC
Strength is inversely proportional to thewater-to-cement ratio
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Strength vs. w/c Ratio for PCC
Strength,psi
w/c ratio
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Whats Important
Good quality materials
PC, water, coarse aggregate, and fine aggregate
Proper Proportioning of the Materials Proper Mixing
Placing and Finishing
Proper Curing QC Testing
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Other Types of Concrete
Lightweight Concrete
Structural and Non-structural (120 50 pcf)
High Density Concrete (400 pcf)
Mass Concrete
Pre-placed Concrete
No Slump Concrete
Roller-Compacted Concrete Shotcrete (Wet and Dry)
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PC does NOT come fromPortland Oregon
History
Portland Cement Limestone + Sand + Clay + Iron ore + heat(1500 C) =
PC Clinker + Grinding = PC powder
Dry process and wet process (p. 22 and 23)
Hydraulic Cement hardens in air and under water
Types I, II, III, IV and V
What does 1 bag of PC weigh?
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Cement kilns are HUGE ...A cement kiln is the word's largest movingmanufacturing machine. Typically, they area huge cylindrical furnace 12 to 25 feet indiameter and 450 to 1,000 feet in length.They are set on a slight incline and rotatefrom 1 to 4 RPM. Cement kilns canprocess up 200 tons of raw material such
as limestone, clay, and sand each hour.Cement kilns are HOT ...Internal temperatures exceed 3,000F,nearly one third the temperature of the
sun's surface.Cement kilns are HUNGRY ...The cement industry is the world's thirdlargest consumer of energy and typicallyuses 12 tons of fuel each hour..
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General Types of Cement
Type I General Purpose
Type II Moderate Heat, Moderate SulfateResistance
Type III High Early Strength
Type IV Very Low Heat
Type V High Sulfate Resistance
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Blended Cements
Type IP or P Portland Pozzolan Cement
Moderate heat and moderate sulfate resistance
Class F Fly Ash 15 to 25% (FDOT 18-22%) High Early Strength
Class C Fly Ash 15 to 40%
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Blended Cements
Type IS or S - Portland Blast Furnace SlagCement
Low Heat (FDOT)
25 70%
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Other Types of Cement
High Early Strength Cements RR Magnesium PhosphateSET-45
Calcium Aluminate Cements- Cement Fondu Calcium SulfoaluminateRapid Set
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RR Mixing Equipment
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Mixing Water
Potable ie. Water suitable for drinking
Chloride < 0.05%
Sulfate < 0.08%
Organic salts < 0.05%
sugar
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Strength vs. w/c Ratio for PCC
Strength,
psi
w/c ratio
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Aggregates
Coarse Aggregate
Retained on #4 Sieve
0.187 in (3/16) or 4.76 mm
Igneous, Sedimentary and Metamorphic rock
Granite
Limestone
River gravel
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CA continued Maximum size from 6-in to 3/8-in
Max size governed by ACI code
Graded down to #4 sieve according to ASTM C136
Standard Specification for Concrete Aggregates
ASTM C33 (Table 5.5, p. 84-5). Common gradations, #467, #57, #67 and #8 (#89-FL)
1-1/2 in max, 1-in max, -in max, and 3/8-in maxrespectively
Aggregate Testing according ASTM Standards
TABLE 5.2 (Page 81), Table 5.6 and 5.7, (page. 92). Dry-Rodded Unit Weight test of coarse aggregate
ASTM C29
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Dry-Rodded Unit Weight of CATest
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Aggregates
Fine Aggregate Passing #4 Sieve
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Fine Aggregate Grading Limits(ASTM and FDOT)
Sieve size % Passing
ASTM C33 FDOT 902
No. 4 95-100 95 - 100
No. 8 80-100 85 - 100
No. 16 50-85 65 - 97
No. 30 25-60 25 - 70
No. 50 5-30 5 - 35
No. 100 0-10 0 - 7
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ASTM C33 Grading Limits
#100 #4
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Sieve Analysis Test
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Aggregate Testing
AASHTO Standards T11, Materials Finer Than 75 m (No. 200) Sieve in Mineral Aggregates by
Washing T19/ T 19M-00, Bulk Density (Unit Weight) and voids in Aggregate T21, Organic Impurities in Fine Aggregates for Concrete
T27, Sieve analysis of Fine and Coarse Aggregates T84, Specific Gravity and Absorption of Fine Aggregate T85, Specific Gravity and Absorption of Coarse Aggregate T96, Resistance to Degradation of Small-Size Coarse Aggregate by
Abrasion and Impact in the Los Angeles Machine
ASTM Standards ASTM D4791, Standard Test Method for Flat Particles, Elongated
Particles, or Flat and Elongated Particles in Coarse Aggregate ASTM D5821, Standard Test Method for Determining the
Percentage of Fractured Particles in Coarse Aggregate
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500 gsample
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Fineness Modulus Calculation
Sieve Size % Retained Cum.%Retained
Cum.%Passing
No. 4 0 0 100
No. 8 10 10 90
No. 16 25 35 65
No. 30 24 59 41
No. 50 26 85 15
No. 100 11 96 4
Pan 4 100 0
Total 285
FM 2.85
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Lab 1 Information
Handouts
Unit Weight of CA
Gradation and FM of Fine Aggregate NO OPEN TOE SHOES
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Unit Weight of CA ASTM C29
Volume of Measure
Unit Weight loose condition
Unit Weight compacted condition
Calculation
1) Calculate the unit weight in both the loose and compact (dense)conditions for the coarse aggregate.
gbulk = (G - T) / Vwhere:gbulk = unit weight of the aggregate, lb/ft
3G = mass of the aggregate plus the measure, lbT = mass of the measure, lb
V = volume of the measure, ft3
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Gradation and FM of
Fine AggregateASTM C136
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500 gsample
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Fineness Modulus Calculation
Sieve Size % Retained Cum.%Retained
Cum.%Passing
No. 4 0 0 100
No. 8 10 10 90
No. 16 25 35 65
No. 30 24 59 41
No. 50 26 85 15
No. 100 11 96 4
Pan 4 100 0
Total 285
FM 2.85
Fi A t G di Li it
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Fine Aggregate Grading Limits(ASTM and FDOT)
Sieve size % Passing
ASTM C33 FDOT 902
No. 4 95-100 95 - 100
No. 8 80-100 85 - 100
No. 16 50-85 65 - 97
No. 30 25-60 25 - 70
No. 50 5-30 5 - 35
No. 100 0-10 0 - 7
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Recycled Concrete Aggregate
Old concrete that has been removed andcrushed to produce aggregate. Coarse aggregate in new concrete
Fine aggregate in new concrete Best combination is CA with natural fine aggregate
Good strength
Drying shrinkage problem
Base-coarse replacement for natural limestone Pervious concrete pavement using recycled
concrete as coarse aggregate.
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Pervious Concrete
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Mineral Admixtures
Pozzolanic (cement replacement)
Class F Fly ash 15 to 25% bwc
Class C Fly ash15 to 40% bwc
Blast Furnace Slag (cement replacement) 25 to 70% bwc
Silica Fume (cement addition)
6 to 12% bwc
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Chemical AdmixturesASTM C-494 (Ch. 6)
Table 6-1
Water Reducing Type A
Set Retarding Type B
Set Accelerating Type C
Water Reducer-Set Retarding Type D
Water Reducer-Accelerating Type E
High Range Water Reducers Type F HR Water Reducer-Set Retarding -Type G
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Air Entraining Agents
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Air-Entraining AgentsASTM C260 (Ch. 8)
Admix that produces stable bubble system
Liquid and solid Low dosage rates relative to other chemical
admixtures (0.005 to 0.05% bwc).
Increase in durability @freeze/thaw Reduces compressive strength
3-5% per percent of entrained air
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Fibers (see Table 7-1)
NaturalEgyptian pyramids
Straw, bamboo, and wood
Glassalkali attack
Steel
Fibers
Synthetic 1 to 1.5 lb per cu. yd.
polypropylene
nylon
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Ethics and Safety
PC The most expensive component of themix
Dont get shorted on this material
Life Cycle Costs vs. Material Costs
PCC inherently a safe material considering:
Highly alkaline
Eye protection Skin irritations
How about the Costs?
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How about the Costs?Item % of Total Cost
ConcreteMaterials
24%
Labor &Equipment
8%
Reinforcing Steel 12%
Labor &Equipment
7%
FormworkMaterials
10%
Labor &
Equipment
39%
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ASTM C143
Size of slump cone
Time to complete test
Sampling 5 min
Start of test 2.5 min
Read to nearest in
Rodding 25 times per layer = 75 times
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ASTM C138
Bucket size
Unit wt calc.
Yield calc
Rodding procedure
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ASTM C231
Air content by pressure method
Rodding procedure
Procedure
Aggregate correction factor
results
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ASTM C173
Air content volumetric
Rodding technique
Method
results