Raw material
for cement
Ground granulated blast-furnace slag (GGBFS) improves the durability of concrete structures as a raw material for Portland blast-furnace slag cement and as a ready-mixed concrete admixture.
For Portland blast-furnace slag cement Type B, it also contributes to decarbonization, reducing CO2 emissions by 42% per ton of cement.
* Portland blast-furnace slag cement Type B is a category of cement defined in Japanese Industrial Standards (JIS)
- Main applications
-
- Concrete structures
-
Granulated blast-furnace slag
Features
-
- 01 Contribution to Resource and Energy Conservation and CO2 Reduction
-
Through the use of Portland blast-furnace slag cement, we contribute to reducing the following environmental factors:
- Resource Conservation: When Granulated blast-furnace slag (GBFS) is used to replace ordinary Portland cement, the consumption of limestone raw materials is reduced, which leads to critical resource conservation and enhances natural environmental preservation.
- Energy Saving: Since GBFS does not require a calcining process via energy-intensive cement kilns, the consumption of coal and other forms of electricity used in cement production can be reduced, resulting in energy cost savings.
- CO2 Reduction: With lower consumption of limestone and energy, CO2 emissions are also reduced. The environmental impact is significant because one metric ton of CO2 is eliminated for every metric ton of slag used in slag cement.
-
- 02 Enhancement of Long-term Strength
-
Compared to ordinary Portland cement, concrete made using Portland blast-furnace slag cement has the distinguishing characteristic of higher long-term strength, making it a preferred product for a wide range of applications, including major infrastructure projects.
-
- 03 Improvement of Durability of Concrete Structures
-
Portland blast-furnace slag cement enhances the durability of concrete structures due to its significant effects in the following areas:
- Inhibition of alkali-aggregate reaction.
- High durability against seawater and chemicals.
- Excellent effect in suppressing chloride ion penetration.
Details
Types of Portland blast-furnace slag cement
| Type | Slag content |
|---|---|
| Portland blast-furnace slag cement Type A | 5〜30％ |
| Portland blast-furnace slag cement Type B | 30〜60％ |
| Portland blast-furnace slag cement Type C | 60〜70％ |
JIS R 5211:2009 Portland blast-furnace slag cement
Portland blast-furnace slag cement manufacturing process
Source: Nippon Slag Association "Steel Slag Environmental Material"
Comparison of CO2 emissions between
Portland blast-furnace slag cement and ordinary Portland cement
"CO2 emissions for every one ton of cement"
Unit: kg
| CO2 emissions source | CO2 emissions from ordinary Portland cement (1) |
CO2 emissions from Portland blast-furnace slag cement Type B (2) |
Reduction in CO2 emissions (1)-(2) |
Reduction in CO2 emissions (%) |
|---|---|---|---|---|
| Limestone | 476 | 270 | 206 | 43 |
| Electricity/energy | 283 | 170 | 113 | 40 |
| Total | 759 | 440 | 319 | 42 |
Source: Nippon Slag Association "Steel Slag Environmental Material"
Example of Blast-furnace slag
composition (Unit: %)
| Component | Blast-furnace slag |
|---|---|
| CaO | 41.7 |
| SiO2 | 33.8 |
| T-Fe | 0.4 |
| MgO | 7.4 |
| Al2O3 | 13.4 |
| S | 0.8 |
| P2O5 | ＜ 0.1 |
| MnO | 0.3 |
Quality standard
| Item | JIS A 6206 standard value (GGBFS 4000) | |
|---|---|---|
| Density (g/cm3) | ≥ 2.80 | |
| Specific surface area (cm2/g) | ≥3500, <5000 | |
| Activity index (%) | Aged 7 days | ≥ 55 |
| Aged 28 days | ≥ 75 | |
| Aged 91 days | ≥ 95 | |
| Flow value rate (%) | ≥ 95 | |
| Magnesium oxide (%) | ≤ 10.0 | |
| Sulfur trioxide (%) | ≤ 4.0 | |
| Ignition loss (%) | ≤ 3.0 | |
| Chloride ion (%) | ≤ 0.02 | |
JIS A 6206:2013 GGBFS for concrete
* Basicity of GBFS used as raw material: 1.60 or greater
Related technical standards
- JIS R 5210:2009 Portland cement, JIS R 5210:2019 (Amendment 1)
- JIS R 5211:2009 Portland blast-furnace slag cement, JIS R 5211:2019 (Amendment 1)
- JIS A 6206:2013 GGBFS for concrete
Our track record
Each year, JFE ships about 6 million tons of GBFS as raw material for cement.
Initiatives to become carbon neutral
