| Cement Basics
» Types of Portland
Portland cements are hydraulic cements composed primarily of hydraulic
calcium silicates. ASTM C150, Standard Specification for Portland
Cement, recognizes ten types of portland cement:
I and Type IA*
General purpose cements suitable for all uses where the special
properties of other types are not required.
Type II and Type IIA*
Type II cements contain no more than 8% tricalcium aluminate (C3A)
for moderate sulfate resistance.
Type II(MH) and Type II(MH)A*
Type II(MH) cements have both a moderate heat of hydration characteristic,
based on a requirement that the sum of C3S+4.75 C3A
<100%, and moderate sulfate resistance properties, based on a
maximum C3A content of 8%.
Type III and Type IIIA*
|What's a Type I/II cement?
Portland cements that meet Type II requirements also must meet
all of the requirements of Type I cements, except those for
compressive strength. Type I/II cements meet both the C3A
requirements of Type II cement and the compressive strength
requirements of Type I cements.
Chemically and physically similar to Type I cements except they are
ground finer to produce higher early strengths.
Used in massive concrete structures where the rate and amount of
heat generated from hydration must be minimized. It develops strength
slower than other cement types.
Contains no more than 5% C3A
for high sulfate resistance.
» Types of Blended
Blended hydraulic cements are produced by intimately and uniformly
intergrinding or blending two or more types of fine materials. The
primary materials are portland cement, slag cements, fly ash, silica
fume, calcined clay, other pozzolans, hydrated lime, and pre-blended
combinations of these materials.
ASTM C595, Specification for Blended Hydraulic Cements,
recognizes three classes of blended cement:
Type IS (X) -Portland blast furnace slag cement
Type IP (X) -Portland-pozzolan cement
Type IT(AX)(BY) –Ternary blended cement
The letters X and Y stands for the percentage of supplementary
cementitious material (SCM) included in the blended cement, and
A and B are the Types of SCMs, either S for slag or P for pozzolan.
Type IS(X), can include up to 95% slag cement. Type IP(X) can include
up to 40% pozzolans. As an example for ternary cements, Type IT(S25)(P15)
contains 25% slag and 15% pozzolans.
» Types of
All portland and blended cements are hydraulic cements. Hydraulic
cement is merely a broader term. ASTM C1157, Performance Specification
for Hydraulic Cements, is a performance specification that includes
portland cement, modified portland cement, and blended cements.
ASTM C1157 recognizes six types of hydraulic cements:
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
Other resources for information on portland cement production and
ASTM C1157, which now includes both blended
and portland cements, moves away from requirements on chemical composition
Results of a survey of cement manufacturers which compiles data
on cement characteristics in 2004.
Portland Cement Characteristics-1998
Results of a survey on cement properties in 1998.
Prescriptive vs. Performance
Specifications for Cements
A description of the differences and some of the potential
benefits and drawbacks of each