Slag cement is a material that is used in a wide variety of commercial and architectural concrete construction applications. This information sheet is intended to provide guidance to specifiers in the absence of slag cement specifications, or for the addition of slag cement to an existing specification.
Slag cement should be used as a pound for pound replacement for a portion of the portland cement in a concrete mixture. Depending on the desired properties or application, various replacement levels can be used. Table 1 lists suggested replacement levels for a variety of common applications.
| Concrete Application
|
SlagCement
|
| Concrete paving
|
25-50%
|
| Exterior flatwork not exposed to deicersalts
|
25-50%
|
| Exterior flatwork exposed to deicer salts with w/cm ? 0.45
|
25-50%
|
| Interior flatwork
|
25-50%
|
| Basement floors
|
25-50%
|
| Footings
|
30-65%
|
| Walls & columns
|
25-50%
|
| Tilt-up panels
|
25-50%
|
| Pre-stressed concrete
|
20-50%
|
| Pre-castconcrete
|
20-50%
|
| Concrete blocks
|
20-50%
|
| Concrete pavers
|
20-50%
|
| High strength
|
25-50%
|
| ASR mitigation
|
25-70%
|
| Sulfate resistance
|
| Type I equivalence
|
25-50%
|
| Type V equivalence
|
50-65%
|
| Lower permeability
|
25-65%
|
| Mass concrete
|
50-80%
|
|
Percentages indicate replacement for portland
cement by mass. These replacement rates are recommended for individual
applications and are based on historical performance. Variations in material
sources and environmental conditions may require alternate substitution rates.
Consult your slag cement supplier for additional assistance.
|
As with all concrete mixtures, trial batches should be performed to verify concrete properties. Listed replacement rate ranges provide a starting point for trial concrete mixture design. These ranges typically accommodate optimization of replacement rates to achieve desired concrete performance in different environments and temperatures. Results may vary due to a variety of circumstances, including temperature and mixture components, among other things. You should consult your local slag cement representative for assistance in how to achieve maximum benefits using slag cement in your concrete project. Nothing contained herein shall be considered or construed as a warranty or guarantee, either expressed or implied, including any warranty of fitness for a particular purpose.
For General Use
Cementitious Materials
1. Portland cement shall conform to the
requirements in ASTM C1501 or ASTM C11572.
2. Slag cement shall conform to the
requirements in ASTM C9893.
3. Blended cement shall conform to the requirements in
ASTM C5954.
4. Pozzolans shall conform to the requirements in ASTM C6185.
5. Silica fume
shall conform to the requirements in ASTM C12406.
6. The water-cementitious materials ratio (w/cm) shall be calculated by
dividing the weight of water by the
weight of portland cement, plus slag
cement plus pozzolans.
Exposure to Sulfates
1. For moderate
exposure, where ASTM C150, Type II cement is required, a Type I with 25 to 50% slag cement (by mass
of cementitious material) can be used.
2. For severe
exposure, where ASTM C150, Type V cement is required, a Type I or a Type II cement with 50 to 65%
slag cement (by mass of cementitious
material) can be used.
3. For very
severe exposure, an ASTM C150 Type V cement with a minimum of
50% slag cement (by mass of cementitious
material) can be used.
4. The sulfate resistance of
the concrete shall be confirmed by testing
in accordance to ASTM C10127.
Mass Concrete
1. For mass
concrete placements, the percentage of portland
cement to be replaced shall be 50 to 80% (by mass of cementitious material).
2. Thermal properties of
the concrete shall be verified prior to construction
to ensure conformity to project requirements.
Alkali-Silica and
Alkali-Aggregate Reactivity
1. Mitigation of ASR shall refer to ASTM
C1778 for guidance; on reducing the risk of alkali-aggregate reaction in
concrete.
When using reactive aggregate, slag
cement shall be used at replacement levels between 25 and 70% (by mass of cementitious material).
3. If
the specific slag/portland cement mixture is
shown to mitigate ASR in accordance with ASTM C1778,
low alkali cement is not necessary.
Exposure to Deicing
Salts
1. Concrete exposed to deicing salts shall
have a
w/cm ratio of 0.45.
2. Concrete shall have an adequate air-void system as defined in ACI
201.2R9.
3. Proper finishing and curing
practices, in accordance with ACI
30210 and ACI 30811 shall be followed.
4. Slag cement replacement can be 25 to 50%
(by mass of cementitious material).
Freeze - Thaw
Durability
1. Concrete shall have a w/cm of 0.45.
2. Concrete shall have an adequate air-void system as defined in ACI
201.
3. Slag cement replacement can be 25 to 80%
(by mass of cementitious material).
1. ASTM C150/C150M-19, “Standard
Specification for Portland Cement,” ASTM International, West Conshohocken, PA, 2019.
2. ASTM C1157/C1157M-17,
“Standard Performance Specification for Hydraulic Cement,” ASTM
International, West Conshohocken, PA, 2019.
3. ASTM C989/C989M-18a, “Standard
Specification for Ground Granulated Blast-Furnace Slag for Use in Concrete and
Mortars,” ASTM International, West Conshohocken,
PA, 2019.
4. ASTM C595/C595M-19, “Standard
Specification for Blended Hydraulic Cements,” ASTM International, West Conshohocken, PA, 20019.
5. ASTM C618-19,
“Standard Specification for Coal Fly Ash and Raw or Calcined Natural
Pozzolan for Use as a Mineral Admixture in
Concrete,” ASTM International, West Conshohocken,
PA, 20019.
6. ASTM C1240-15, “Standard Specification
for Use of Silica Fume for Use as a
Mineral Admixture in Hydraulic-Cement
Concrete, Mortar, and Grout,” ASTM International, West Conshohocken, PA, 20019.
7. ASTM C1012/c1012M-18b,
“Standard Test Method for
Length Change of Hydraulic-Cement Mortars Exposed to a Sulfate Solution,” ASTM
International, West Conshohocken, PA, 2019.
8. ASTM C1260-14,
“Standard Test Method for
Potential Alkali Reactivity of Aggregates (Mortar-Bar Method),” ASTM
International, West Conshohocken, PA, 2019.
9. ASTM C1778- 19, “Standard Guide for
Reducing the Risk of Deleterious Alkali-Aggregate reaction in Concrete,” ASTM
International, West Conshohocken, PA, 2019.
10, ACI 201.2R-16, “Guide to Durable
Concrete,” American Concrete Institute, Farmington Hills, MI, 2016.
11. ACI 302.1R-15, “Guide
to Concrete Floor and Slab Construction,”
American Concrete Institute, Farmington Hills, MI, 2015.
12. ACI 308.1-11, “Standard
Specification for Curing Concrete,”
American Concrete Institute, Farmington Hills, MI, 2011.
“As with all concrete
mixtures, trial batches should be performed to verify concrete
properties. Results may vary due to a variety of circumstances, including
temperature and mixture components, among other things. You should
consult your slag cement professional for assistance. Nothing contained
herein shall be considered or construed as a warranty or guarantee, either
expressed or implied, including any warranty of fitness for a particular
purpose.”