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

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Fundamentals of Concrete 2010

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