Advanced Topics in Civil Engineering Progress in Concrete ...courses/atce1/progress.pdf · Progress in Concrete Technology ATCEATCEATCE-I --I I Advanced Topics in Civil Engineering

Progress in Concrete Technology

Advanced Topics in Civil EngineeringATCE-I ATCEATCEATCE---I I I

Professor Kamran M. Nemati

First Semester 2006 1

Advanced Topics in Civil Engineering

ATCE-I ATCEATCEATCE---I I I

Progress in

Concrete

Technology


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� Approximately 35 percent of the bridges in the United States are classified as deficient (The 1993 report of the secretary of transportation to the U.S. Congress)

� structurally deficient (21 percent)

� functionally obsolete (14 percent)

� The Federal Highway Administration (FHWA) estimates that the cost to maintain current overall bridge conditions is estimated at $5.2 billion annually.


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� Portland Cement Types:

� Type I General Use

� Type II Moderate sulfate resistance or moderate heat

� Type III High early strength

� Type IV Low heat of hydration

� Type V Sulfate resistant






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Progress in Concrete TechnologyProblem:

� Low Strength/Weight Ratio

60pcf 500

psi 30,000 :Steel = 20

pcf 150

psi 3,000 :Concrete =

� To improve the ratio:� (a) Lower the density

� (b) Increase the strength

66pcf 150

psi 10,000 :HSC = 100

pcf 100

psi 10,000 :LWAC =

High-Strength Concrete Light-Weight Aggregate Conc.


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� Lightweight Concrete

� High-Strength Concrete

� High Workability or Flowing Concrete

� Shrinkage Compensating Concrete

� Fiber-Reinforced Concrete

� Concrete Containing polymers

� Heavyweight Concrete

� Mass Concrete

� Roller-Compacted Concrete



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Structural Lightweight Concrete

� Definition:

� 28-day f ’c ≥ 2,500 psi

� Unit weight: Min: 90 pcf

Max: 110 pcf

� Microstructural Properties:

� Dense, strong transition Zone due to pozzolanic reaction.

� Strength more influenced by aggregate characteristics than by transition zone.






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Durability� Freeze-Thaw Resistance

� Permeability

� Creep / Drying Shrinkage

� Abrasion / Erosion Resistance



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Applications� Lower overall cost of the structure

� Bridge Decks

� Floor slabs

� Pre-cast concrete elements







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High-Strength Concrete� Definition:

� 28-day f ’c ≥ 6,000 psi (40 MPa)

� Materials and mix proportions:

� Key: POROSITY in 3 phases

� Problem: Mixing, placing, and consolidation

� Use: Water-Reducing Admixture.

9,000 psi0.34

7,500 psi0.36

6,000 psi0.38

f ’cW/C Ratio

Water/Cement Ratio


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High-Strength Concrete






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Concrete Damage

Due to Earthquake

Cypress StructureOakland, California

October 17, 1989


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San Francisco Earthquake - 1989






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Documents

Advanced Topics in Civil Engineering Progress in Concrete ...courses/atce1/progress.pdf · Progress in Concrete Technology ATCEATCEATCE-I --I I Advanced Topics in Civil Engineering