Cement Types - KOCWcontents.kocw.net/KOCW/document/2014/hanyang/ryoujaesuk1/... · 2016. 9. 9. ·...
Transcript of Cement Types - KOCWcontents.kocw.net/KOCW/document/2014/hanyang/ryoujaesuk1/... · 2016. 9. 9. ·...
Cement Types
Type Use C3S C2S C3A C4AF Comments
I general 45-55 20-30 8-12 6-10 no limits on 4 principal components
II general/
mod sulfate resistance/
mod heat of hydration
III high early strength
IV low heat of hydration
V high sulfate resistance
New Performance-based Specification for
Portland Cements
ASTM C 1157 Standard Performance Specification for Hydraulic Cement
Type GU General use
Type HE High-early strength
Type MS Moderate sulfate resistance
Type HS High sulfate resistance
Type MH Moderate heat of hydration
Type LH Low heat of hydration
Option R Low reactivity with alkali-reactive aggregates
Other Cement Types
• Type IA, Type IIA, Type IIA
• Blended cements (e.g., Types IP, IS, ISM, IIP, IIS, etc)
• White portland cement
• Masonry cement
• Expansive cements
• Calcium aluminate cements
• Rapid setting cements
• Oil well cements
Microstructure
Solids
• C-S-H
• CH
• Ettringite
• Monosulfate hydrate
• Residual unhydrated cement
Voids
• Entrapped air (>1mm)
• Entrained air (75-500um
• Capillary pores (macro →
meso)
• Interlayer space (micropores)
Water
• Capillary water
• Adsorbed water
• Interlayer water
• Chemically combined water
Microstructure
Solids
Interfacial Transition Zone
The ITZ is the region 10-50um
wide around coarse aggregate;
characterized by:
• Higher local porosity
• Greater density of pre-
existing microcracks
• Larger CH crystals that tend
to be oriented and more prone
to cleavage.
WEAK link in concrete!
By tailoring the concrete mixture to reduce the influence of the
ITZ, strength, E, and impermeability are increased.
• lower w/c
• higher cement content
• use of SCMs
• smaller MSA
• reactive dolomitic aggregate
• lightweight aggregate
• extended moist curing
Interfacial Transition Zone