• Korean Journal of Materials Research
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• v.13 no.2
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• pp.94-100
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• 2003

The interface between low carbon steel and blended cement pastes containing slag was investigated using impedance spectroscopy. In addition, the pastes were characterized by several analytical methods (XRD, EDX, electrode potential, pH and ICP). The electrical behavior of the interface in the blended slag systems is correlated to its corresponding pore solution chemistry and the products present in the interface. Passivation occurred at the paste/steel interfaces, in cement pastes up to containing from 0 to 75% slag content. 100% slag paste induced corrosion of the low carbon steel, which could be explained by the influence of sulfur on the system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.144-145
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• 2014

In the cement,that is the main materials of the panel, as to the cofired process, more than 1,300 enormous energies is consumed, in addition the greenhouse gas generated in the process of producing the cement occupies 6.3% of the country whole emission quantity. And the carbon dioxide of about 0.8 ton is the cement ejected in 1 production. Accordingly, the panel utilizing the industrial byproduct is developed. Accordingly, this research is the experiment which makes the individual size into the environment-friendly inorganic binder panel and by using the blast furnace slag, which is the industrial byproduct with the cement substitute material red mud, silica fume, and etc. looks at the dry shrinkage. The length variation in which the panel which is 450 with the dry shrinkage result of measurement, thickness 12mm, and size 450mm is the smallest was shown.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.721-724
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• 2006

In this study, particle size distribution of cement powder system were adjusted using the blast furnace slag powder, Blaine $2250cm^2/g\;and\;8300cm^2/g$, which easy to adjust particle size distribution to examine how particle size distribution of the binder has an effect on rheological properties of the cement paste. In addition, the relationship between n-value of Rosin-Rammler function and plastic viscosity were discussed. All measured flow curves represented thixotropy behavior and the hysteresis area was smaller for the more added coarse particle. When the combination was based on a ratio of $20{\sim}25vol%$ fine particles, $30{\sim}40vol%$ OPC and $40{\sim}45vol%$ coarse particles of the total volume, a high fluidity and low yield strength was achieved.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.33-40
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• 2013

The cement industry brought very severe environment problems with massive carbon dioxide during its production. To solve this problem, attempts on Alkali-Activated Slag (AAS) concrete that perfectly substitutes industrial by-products such as ground granulated blast furnace slag (GGBFS) for cement are being actively made. AAS concrete is possible to have high strength development at room temperature, however, it is difficult to ensure the working time due to the fast setting time and the loss of workabillity because of the alkali reaction. In this study, the early age properties of alkali activated slag mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The water-binder ratio (W/B) was fixed at 0.35 and sodium hydroxide and waterglass as alkali activator was used. The compressive strength, the flow and the ultrasonic pulse velocity were measured according to the type of superplasticisers, which were naphthalene(N), lignin(L), melamine(M) and PC(P), up to a maximum of 2 percent by the mass of GGBFS. The results showed that adding melamine type of superplasticizer improved the fluidity of AAS mortar without decreasing the compressive strength, while naphthalene and polycarbonate type of superplasticizer had little effect on the fluidity of AAS mortar.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.63-69
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• 2012

Recently, the cement industries brought very severe environment problems such as resource depletion and global warming with massive carbon dioxide during its production. The number of cases using industrial by-products such as the ground granulated blast furnace slag (GGBFS) in concrete mixtures is increasing to resolve the environmental issue. GGBFS is mainly used in the range between 20 to 50% to replace cement, but nowadays lots of researches are carried out to develop the alkali-activated slag (AAS) concrete with no cement. In this study, the early age properties of alkali activated slag (AAS) mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The experimental variables were the water-binder ratios of 0.3, 0.4, and 0.5 and NaOH as the alkali activator of 4%, 8%, and 12% by the mass of GGBFS, and compressive strength, flow, setting time, and ultrasonic pulse velocity of AAS mortars were measured and analyzed. It is found from the test results that as the normal concrete the lower W/B, the higher compressive strength. However, superplasticizer has to be used for producing high strength AAS concrete because the workability of AAS mortar are significantly lowered.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.5
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• pp.9-17
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• 2009

In this paper, we describe a flow meter system for pulverized coal developed for the pulverizer-burner system of a boiler or blast furnace, which uses the density and the velocity of the granule flow. The granule flow density is measured by a sensor that detects the capacitance from the electrode on the surface of the piping system. The velocity of granule flow can be calculated using the distance between two pairs of built-in sensors in the flow direction, the time obtained from the sampling cycle using the correlation method between two waveforms of the sensors. The flow rate is calculated from the density and velocity of the granule flow. The reliability and accuracy of the flow meter system has been verified by comparing the data with the weight measured from a load-cell.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.61-67
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• 2008

In this papar, the flow meter system for pulverized coal is developed for the pulverizer-burner system of the boiler or the blast furnace. The sensor of the system a lied the capacitance with a pair of electrode on the outer wall of the electric insulator pipe. The circuit is designed for the measurement of the granule flow density combining as a measuring electrode and a reference. In order to measure granule-flow density, the calibration curve between the weight measured from loadcell and the voltage from the circuit is created. It is verified that the flow meter system has reliability and accuracy using on-line test.

• Journal of The Korean Digital Architecture Interior Association
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• v.12 no.3
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• pp.59-66
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• 2012

Autoclaved Lightweight Concrete(ALC) features such as a high performance insulation, the fire resistance, the advantage of easy handing construction, and lightweight panels applied the curtain wall system. ALC materials are certified as non-toxic environmental and eco-friendly productions. But ALC external panels mixed with blast furnace slag pounder and silica fume have to be coated with a stucco compound or plaster because of resisting the ambient environment. This study is that mixing tests to evaluate a performance analysis of exterior paints to be make-up pigments(organic or inorganic) coated with panel surface. Testing compared by KS F 2476; flow test, KS F 2426; compression strength test, KS F 2762; bond strength test. In results, the case of the inorganic binder, ratio of alumina cement : anhydrite is 90:10 to 80:20 at the highest level of intensity. In the case of the organic binder, adhesive strength rating at surface of ALC, the pullout strength is below 0.5 $N/mm^2$ but the normal concrete is over 2.0$N/mm^2$. A contents ratio of EVA resin is more than 3% and then bond strength is effectively.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.56-63
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• 2020

The usage of OPC-free alkali activated ground granulated blast furnace slag(GGBS) mortar has been widely studied on the previous years, due to its advantages on sustainability, durability and workability. This paper brings a new view, aiming to classify the best application in situ for each mortar, according to the type and activator content. By this practical implication, more efficiency is achieved on the construction site and consequently less waste of materials. In order to compare the different activators, the following experiments were performed: analysis of compressive strength at 28 days, setting time measured by needles penetration resistance, analysis of total pore volume performed by MIP and permeability assessment by RCPT test. In general, activated GGBS had acceptable performance in all cases compared to OPC, and remarkable improved durability. Following the experimental results, it was confirmed that each activator and different concentrations impose distinct outcome performance to the mortar which allows the classification. It was observed that the activator Ca(OH)2 is the most versatile among the others, even though it has limited compressive strength, being suitable for laying mortar, coating/plaster, adhesive and grouting mortar. Samples activated with NaOH, in turn, presented in general the most similar results compared to OPC.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.497-503
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• 2003

Supplementary cementitious materials (SCM) such as fly ash, ground granulated blast furnace slag and silica fume are now being extensively used in concrete to control expansion due to alkali-silica reactivity (ASR). However, the replacement level of a single SCM needed to deleterious ASR expansion and cracking may create other problem and concerns. For example, incorporating silica fume at levels greater than 10％ by mass of cement may lead to dispersion and workability concerns, while fly ash can lead to poor strength development at early age, The combination of silica fume and fly ash in ternary cementitious system may alleviate this and other concerns, and result in a number of synergistic effects. The aim of the study was to enable evaluation of more realistic suitability of a silica fume-fly ash combination system for ASR resistance based on an in-house modification of ASTM C 1260 test method. The modification can be more closely identified with actual field conditions. In this study three different strengths of NaOH test solution(1N, 0.5N, and 0.25N) were used to measure the expansion characteristics of mortar bar made with a reactive aggregate. The other variable included longer testing period of 28 days instead of a conventional 14 days.