Soil-Structure Interaction Seminar - Foundation Performance ...

Concrete
Comprised of: Fine & Coarse Aggregate, Cement and Water
Cements - "Portland Cement" - a hydraulic cement consisting essentially of
hydraulic calcium silicates usually containing one or more forms of calcium sulfate .
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Type I - Most common everyday use
Type II - Used for moderate sulfate resistance or moderate heat of hydration applications
Type ill - High early strength requirements
Type IV - Low heat of hydration applications
Type V - High 'sulfate resistance applications
Type K - Shrinkage compensation cement (Expands frrst & then shrinks)
Add the letter "A" to type to specify air entrainment. (Always Use)
The "Air" consists of large number of minute air bubbles in the cement paste and have
spacings of less than 0. 008 inches.
Admixtures:
Fly Ash:
Accelerators - avoid use of calcium chloride
Water reducing and set controlling - 4 classes
Class 1 & 3 are water reducing and set retarding
Class 2 & 4 are water reducing but usually do not change set time.
Three (3) types or class-obtained from burning ground or powdered coal (Class "F" &
"C") Class "N" - natural
Class "N" -Calcined natural pozzolans (not usually considered)
Class "F" -Burning anthracite or bituminous coal- contains some pozzolans
Class "C" - Burning lignite or subbituminous coal - contains pozzolans and has
cementitious property
Note: Only Class "C" can replace cement in concrete BUT NEVER MORE THAN 20%