• Journal of the Korea Institute of Building Construction
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• v.24 no.1
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• pp.11-21
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• 2024

This research elucidates the fundamental properties of carbon dioxide (CO₂)-cured mortar as influenced by varying substitution rates of blast furnace slag fine powder. The findings indicate that CO₂ curing enhances the formation of calcium carbonate (CaCO₃), contributing to pore reduction and the early development of strength. While calcium hydroxide (Ca(OH)₂) plays a more pivotal role in the primary development of strength compared to CaCO₃, an increase in the substitution rate of blast furnace slag fine powder results in reduced production of Ca(OH)₂. Nonetheless, the maintenance of strength through CaCO₃ formation is observed even after the depletion of Ca(OH)₂, suggesting that the required performance can be sustained post-exposure to the atmosphere following CO₂ curing. It is noted that substitution rates exceeding 50% lead to performance deterioration due to CO₂, highlighting the necessity for careful adjustment of the substitution ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.353-354
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• 2009

The different sized slag powder, which have been used widely as a cement binder, was obtained by using 3 kind of mills. Two kinds of slag powder with different size was mixed and then investigated the relationship between the rheological properties and the particle packing ratio or particle distribution. It was found that the rheological properties of two mixed slag powder was proportional to the particle packing ratio of it. And the paste flowability of the mixed slag powder with wide particle distribution was very good.

• KIEAE Journal
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• v.12 no.3
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• pp.115-122
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• 2012

Based on previous research and existing literature, this study examines the development of admixture, which increases the early concrete strength (1 and 3 day) by mixing blast furnace slag cement and concrete stimulant. The research on early strength development of concrete is necessary in dealing with the drawbacks of slow early strength concrete on site and to shorten the construction time. The study confirmed that when a high alkaline mortar mixture is mixed with blast furnace slag, the early strength of admixture exceeds that of ordinary portland cement (OPC). The use of calcium chloride ($CaCl_2$) promotes hydration of cement at low temperature and show similar strength as the blast furnace slag admixture. Although calcium chloride seems economically advantageous, it causes steel corrosion and its use in concrete should be further studied in-depth.

• Journal of the Korea Institute of Building Construction
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• v.13 no.1
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• pp.29-37
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• 2013

In this study, a zero-cement brick is manufactured by replacing cement with recycled aggregates and blast furnace slag powder. Experimental tests were conducted with standard sized samples of $190{\times}57{\times}90mm$ (KS F 4004), and this manufacturing technique was simulated in practice. Results showed that the zero-cement brick with 0.35 W/B had the highest compressive strength, but the lowest absorption ratio. This absorption ratio of zero-cement brick with 0.35 W/B was lower than the required level determined by KS F 4004. Hence, to increase the absorption ratio, crushed fine aggregate (CA) and emulsified waste vegetable oil (EWO) were used in combination in the zero-cement brick. It was found that the zero-cement brick with CA of 20% and EWO of 1% had the optimum combination, in terms of having the optimum strength development (12 MPa) and the optimum absorption ratio (8.4%) that satisfies the level required by KS. In addition, it is demonstrated that for the manufacturing of zero-cement brick of 1000, this technique reduces the manufacturing cost by 5% compared with conventional cement brick.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.126-127
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• 2013

For the decades, various of materials were used to instead of cement as the high volume CO₂ occurred during the process of cement manufacture. In this paper, incineration plant ash was used in the mortar which incorporating high volume of blast furnace slag. Water to binder ratio(W/B) is fixed as 50%,BS+RP's replacement ratio is fixed as 80%,and the replacement ratio of WA1 is range as 0,0.5,1,2,3,4,5%.For the fresh mortar, flow and chloride contents has been tested. For the hardened mortar, compressive strength at 3,7,28 days has been tested. the result shows that when the replacement ratio of WA1 is 0.5%,the chloride contents is less than 0,3 kg/m3,the flowability and strength also performed better than other replacement types of mortar.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.37-38
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• 2013

The fine powder obtained from the manufacturing process of recycled coarse aggregate contains unhydareted cement particles on their surface. It is believed that the alkalinity of the powder (11.0-12.5) is enough to active the slag-based composites. In this paper, the obtained powder was sieved and divided into two sizes, i.e., 0.08 mm and 0.3 mm, and added to the slag-based mortar. Results showed that the fine powder had an effect on the slump and the compressive strength of slag-based composites. With the different pH values of the powder, it could be seen that the distance between the two level powders. And found the peak 28 days compressive strength as the replacement ratio of the recycled aggregate powder changed. The findings from this study provide an indication that with achieved compressive strength, the fine powder can be used in a light weight concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.257-258
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• 2012

With regard to the carbon reduction that has become an international problem, we have examined the effects of compressive strength of the ground granulated blast-furnace slag mortar with the curing temperature. Also, we evaluated the mechanical properties of steel slag powder produced during the steelmaking process in order to examine the possibility as admixture.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.30-31
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• 2013

In this study, characteristics of the concrete replaced in large amount with blast furnace slag is analyzed by the microscopic analyses in the process of the mock-up testing to apply to the actual practice in the area of the general strength by activating a small amount of cement(25%) replaced in large amount of finely powered blast furnace slag.

• Journal of the Korea Institute of Building Construction
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• v.13 no.4
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• pp.351-359
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• 2013

Blast furnace slag (BFS) have many advantages that are related to effective value improvement on applying to concrete while side effects of blast furnace slag also appear. Thus, research team conducted an experiment with high volume slag to see if the attribute of waste alkali accelerator for mixing rate, mixed use of NaOH and $Na_2SiO_3$, and early strength agent for mixing rate for replacement ratio and for the types of the stimulants in order to increase the use of blast furnace slag1s powder. As the result of the experiment, when it comes to compression strength, all of the alkali stimulants have been improved as the replacement rate increases except for sodium hydroxide. Among the alkali stimulants, sodium silicate was high on dynamic elastic modulus and absorption factor. In case of early strength agent, the mix of mixing 1.5% and blast furnace slag 75% have showed high strength enhancement. In event of Waste Alkali accelerator, it has showed different consequences for each experiment.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.207-210
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• 1999

This experimental study was carried out to estimate the effects of mixing dosage rate and blaine on the mechanical properties of concrete admixed with ground granulated blast-furnace slag (BFS) powder. According to the test results, compressive strength of concrete admixed with slag not more than 35% was at least 80% of compressive strength of OPC concrete at 3 days age, and much bigger than that of OPC concrete at 28 days age. Consequently, in order to apply the BFS to the concrete is demanded, and rigorous construction management should be followed.