• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.387-394
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• 2008

The Physical property changes of calcined clay by carburization were investigated studied. The carburization mechanism is the penetration of carbon which occurred during incomplete fuel combustion into crevice of clay structure. The experiments for elasticity and freeze-thaw resistance were conducted, and the results can be summarized as follows: Dynamic modulus of elasticity and also freeze-thaw resistance of calcined clay by carburization treatment increased more than 92% after testing 300 cycle, which was more improved than 88% of calcined clay. Therefore, it can decrease the possibility of winter-sowing, which is one the weakness of calcined clay. It is on the basis of the fact that the porosity of calcined clay by carburization treatment is about 12%, which indicates smaller pore spaces comparing with the 14% of porosity of calcined clay and those values were calculated by apparent porosity show and also supported by SEM images. Infrared emissivity of calcined clay by carburization treatment and calcined clay were respectively 0.92 and 0.9l at $80^{\circ}C$. However, those values were 0.91 and 0.88 at $200^{\circ}C$, which means infrared emissivity of calcined clay by carburization treatment shows 3.6% higher than the calcined clay. Moreover, within the wavelength range from 3 to $7\;{\mu}m$, while the calcined clay had low infrared emissivity, the calcined clay by carburization treatment had increased infrared emissivity. It is inferred that it was affected by carbon element that has high infrared absorptivity within this wavelength range.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.3
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• pp.109-113
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• 1999

The objective of this research was to develop growth media for artificial ground by blending calcined clay and coconut peat. To achieve this, aggregates of clay particles were mixed with disel oil and heated to high temperature(1150~120$0^{\circ}C$) to expand clays. The particle sizes of expanded clay were controlled to 2~5mm in diameter. Then expanded clayes were mixed with coconut peat and changes of soil physicochemical properties and their effect on plant growth of Hedera L. were determined. The infiltration rate of calcined clay was very high, but the water holding capacity, the cation exchange capacity(CEC), and the nutrient contents were low. The characteritics of coconut peat was vice verse to calcined clay. This indicates that the mixture of calcined clay and coconut peat have the better characteristics than each material. As compared to mineral soil, the infiltration rate, the water holding capacity, the CEC and the nutrient contents increased, but bulk density decreased to about 1/4. And, Hedera L. grown in the mixture of calcined clay and coconut peat(6:4, v/v) had higher plant height, longer leaf length, more total number of leaves per plant and fresh weight than that grown in mineral soil, but statistical differences were not observed between two treatments.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.133-134
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• 2021

Limestone-calcined clay-Cement (LC3) concrete provides a solution for sustainability, durability, and profitability of concrete industry. This study shows experimental studies of the macro properties (residual compressive strength), the meso properties (mesoscopic images), and micro properties (thermogravimetric (TG) analysis, X-ray powder diffraction (XRD), FTIR spectra, Raman spectra, Mercury intrusion porosimetry, and SEM) of LC3 paste with various mixtures and at high elevated temperatures (20 ℃, 300 ℃, 550 ℃ and 900 ℃). We find (1) Regarding to macro properties, LC3 cementitious materials are at a disadvantage in compressive strength when the temperature is higher than 300 ℃. (2) Regarding to meso properties, when the temperature reached 550 ℃, all samples generated more meso cracks. (3) Regarding to micro properties, first, as the substitution amount increases, its CH content decreases significantly; second, at 900 ℃, for samples with calcined clay, a large amount of gehlenite crystalline phase was found; third, at elevated temperatures (20 ℃, 300 ℃, 550 ℃ and 900 ℃), there is a linear relationship between the residual compressive strength and the cumulative pore volume; fourth, at 900 ℃, a large amount of dicalcium silicate was generated, and damage cracks were more pronounced. The experimental results of this study are valuable of material design of fire resistance of LC3 concrete.

• Structural Engineering and Mechanics
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• v.89 no.4
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• pp.349-362
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• 2024

High-performance fiber-reinforced cement composites (HPFRCC) are new materials created and used to repair, strengthen, and improve the performance of different structural parts. When exposed to tensile tension, these materials show acceptable strain-hardening. All of the countries of the globe currently seem to have a need for these building materials. This study aims to create a low-carbon HPFRCC (high ductility) that is made from materials that are readily available locally which has the right mechanical qualities, especially an increase in tensile strain capacity and environmental compatibility. In order to do this, the effects of fiber volume percent (0%, 0.5%, 1%, and 2%), and determining the appropriate level, filler type (limestone powder and silica sand), cement type (ordinary Portland cement, and limestone calcined clay cement or LC3), matrix hardness, and fiber type (ordinary and oxygen plasma treated polypropylene fiber) were explored. Fibers were subjected to oxygen plasma treatment at several powers and periods (50 W and 200 W, 30, 120, and 300 seconds). The influence of the above listed factors on the samples' three-point bending and direct tensile strength test results has been examined. The results showed that replacing ordinary Portland cement (OPC) with limestone calcined clay cement (LC3) in mixtures reduces the compressive strength, and increases the tensile strain capacity of the samples. Furthermore, using oxygen plasma treatment method (power 200 W and time 300 seconds) enhances the bonding of fibers with the matrix surface; thus, the tensile strain capacity of samples increased on average up to 70%.

• Journal of the Korean institute of surface engineering
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• v.41 no.2
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• pp.63-68
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• 2008

Traditionally and generally used calcined clay was carburized, and its characteristics were studied. Carburization treatment was performed by the thermally decomposed carbon and the deposit carbon which occur in a so called 'Boudouard reaction $(2CO{\rightarrow}CO_2+C)'$ at fuel combustion process in a closed-type furnace. The color of the carburized calcine clay changed from yellow to black, and the carbon component revealed as crystalline graphite by the X-ray diffraction test. The weight of the carburized calcine clay decreased to about 4 wt.% by the 1st heating to $1400^{\circ}C$ in air but it does not decreased by the 2nd heating of the same conditions. By the carburization treatment, the water absorption changed from 13 wt.% to 6 wt.%, and the contact angle for water drop changed, too, from 0 to $87^{\circ}$ which was tested by the photograph of one minute after a water drop contact. It means the carburized calcine clay does not absorb water drop so it has a hydrophobic characteristic.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.3 s.31
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• pp.207-222
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• 1989

New process for the preparation of the artificially soild cloth (ASC) used for detergency evaluation was developed and its detergency was also studied. ASC was prepared by the dipping of cotton cloth in the water in which oily soil, protein (gelatine), carbon black and clay had been dispersed. The clay used for this ASC was red yellowish soil around Mt. Kumjung and was a typical soil in Pusan area. Adhesive status of soil at prepared ASc was examined by an electron microscope, and crystallyzation and color change of used clay were evaluated with the determination of X-ray diffraction and surface reflectance. For the evaluation of detergency by the washing with commercial and model detergents, the behavior of soil removal from this ASC comparing with naturally soiled collar cloth was examined. Those results are summerized as followings; 1) Adhesive ststus of soil at prepared ASc was very similar to that of naturally soiled collar cloth. 2) A crystalline of clay calcined at $800^{\circ}C$ was disappeared in part and color of calcined clay changed into reddish yellow by the decomposition of organic matters. 3) More uniform ASc was prepared with clay calcined at $800^{\circ}C\;that\;200^{\circ}C$ however its detergency prepared from clay calcined at $800^{\circ}C$ was poor 4) A significant relationship between the content of inorganic matter in ASc and K/S value was found, however no significant result between the content of protein contaminated and K/S value was observed. 5) Detergency of prepared ASc had a very similar to that of naturally soiled collar cloh.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.695-698
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• 2005

Ever since man learnt to build homes and cities around 10,000 years ago, clay materials has undoubtedly been one of the most widely-used construction materials in the world. However, the clay has poor strength, water resistance and durability, thus being limitedly used as calcined clay after being calcined. Pozzolan materials is to improve the strength and the durability of concrete as a result of the pozzolanic reaction. Therefore, the purpose of this study is to analyzes ingredient about clay mineral about Chung-buk area 10 places and to examine the application of clay minerals for the concrete admixtures.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.4
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• pp.239-246
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• 2008

This research tried to find out the optimum fabrication method of calcined clay granules comprising zeolite. Kaolin clay and natural zeolite powder were used as raw materials of calcined clay, and silica stone powder was used for controlling the porosity of the granules. The granulation was performed with two kinds of granulators: a pan granulator and a high-shear mixer granulator. Various granules were fabricated by the mixing ratios and the rotation speeds of the granulators, and were heated from 400 to $700^{\circ}C$ at $100^{\circ}C$ interval. The crushing strength, pore size distribution, and CEC of the granules were measured. The evaluation method for the resistance of granules to human treading was created and the tests were conducted at dry and wet conditions. The resistance and crushing strength improved in proportion to the rotation speed of the granulator and the heating temperature, but the CEC decreased. The pellet made by the pan granulator did not have the strength against treading upon heating to below $700^{\circ}C$, but the pellet made by the high-shear mixer granulator endured the treading test upon heating to over $500^{\circ}C$

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.151-152
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• 2023

This study investigates the effect of nano-silica and nano-calcite on the hydration properties and mechanical performance of limestone calcined clay cement (LC³) paste. The pastes were synthesized by replacing limestone with nano-silica and nano-calcite in order to enhance the mechanical properties in both early and late stages of hydration. The nano-calcite enhanced the strength of LC³ pastes at 1 day of hydration, however, the strength decreased compared to the ordinary LC³ pastes afterwards due to excessive amount of carboaluminate produced in the pastes. On the other hand, nano-silica improved the mechanical properties of LC³ pastes at all ages of hydration. This is mainly due to the nucleation effect and pozzolanic reaction of nano-silica, affecting the early age and late ages of hydration, respectively. The nucleation effect of both nanomaterials were confirmed by the analysis of hydration heat, supporting the enhanced early age strength of nanomaterial incorporated LC³ pastes. Furthermore, the dense matrix was shown in the pore size distribution, and the increased C-S-H due to the pozzolanic reaction evidence the improved compressive and splitting tensile strength of nano-silica incorporated LC³ pastes.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.5
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• pp.107-115
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• 2002

This study was carried out to compare artificial soil formulated by blending calcined clay and coconut peat with perlite, then to evaluate this soil as a perlite substitute for use as an artificial planting medium. To achieve this, a determination of the physico-chemical properties and it's effect on plant growth were conducted by comparing those with large perlite grains and small grains. The results are summarized as follows: 1) The bulk density was 0.41g/㎤. This density was lower than that of field soil, but higher than that of large perlite grain(0.23g/㎤) and small grain(0.25g/㎤). The porosity, field capacity, and saturated hydraulic conductivity were 71.3%, 49.2%, and 3.8$\times$10-2cm/s, respectively. The air-permeability, water holding capacity, and drainage were better than or equal to that both large and small perlite grain. 2) It was near-neutral in reaction(pH=6.6). It had a high organic carbon content(65.8g/kg) and a low available phosphoric acid content(84.7mg/kg). It was similar to crop soil in cation exchange capacity(11.4cmol/kg). It had a low exchangeable calcium content(0.71cmol/kg), a low exchangeable magnesium content(0.68cmol/kg), a high exchangeable potassium content(2.54cmol/kg), and a high exchangeable sodium content(1.12cmol/kg). Except for the exchangeable potassium and sodium content, the chemical properties were better than or equal to both large and small grain perlite. The excessive exchangeable potassium or sodium content will inhibit plant growth. 3) In Experiment 1, the plant growth tended to be higher compared to that of large and small perlite gains. But in Experiment 2, it tended to be lower. This might be linked to the excessive exchangeable potassium or sodium content. 4) It could be considered as a renewable perlite substitute for greening of artificial soil. But, it would be necessary to leach the excessive exchangeable potassium or sodium to avoid the risk of inhibiting plant growth.