• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.36-37
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• 2015

The purpose of this study is to investigate pozzolanic reactivity of the rice straw ash. This study focused on rice straw ash properties at various burning temperature and duration as a mineral admixture for mortar and concrete, and provide the crystalline state and molecular structure of rice straw ash. X.R.D and N.M.R were performed on rice straw ashes to identify pozzolanic reactivity.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.531-536
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• 2014

Recently, the amounts of dredge sea soil in south Korea have been increasing because of various maintenance works at harbors and rivers. Dredged sea soil contains various contaminants. Hence, prior to recycling the dredged sea soil, the various contaminants should be removed to prevent a secondary contamination due to the leaching of hazardous chemicals. Pretreated dredged sea soil can be buried under the ground or used for land reclamation. In this study, however, pretreated dredged sea soil was used to investigate the level of pozzolanic activity. The properties of pretreated dredged sea soil were investigated, the method for heat treatment was determined, and the compressive strength of mortar using dredged sea soil was examined. According to the XRF result, the main components of dredged sea soil were $SiO_2$ of over 55%, and $Al_2O_3$ and $SO_3$ of some amounts. Results from XRD and TG/DTA showed that pretreated dredged sea soil can be used as a pozzolanic material. When dredged sea soil was thermally treated for 90 min at $550^{\circ}C$, a compressive strength result was similar to that of control mortar.

• Cement Symposium
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• s.35
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• pp.109-114
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• 2008

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.519-523
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• 1996

Calcium hydroxide produced by cement hydration decreases the durability and the compressive strength of cement mortars. Pozzolanic property of meta kaolin and silica fume allows to avoid this drawback. Calcium hydroxide consumption according to pozzolanic raction is evaluated by Fourier differential thermal analysis. Particulary the properties of high performance and high strength of cement mortar containing above 10% meta kaolin and silica fume were resulted in the pozzolanic activity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.85-90
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• 2002

This study aims to propose a fundamental report for pozzolan reaction of discarded Bentonite by heat-treatment as concrete mineral admixture. As discarded bentonite is clay mineral to contain a great quantity a lot of $SiO_2$ and $Al_{2}O_{3}$, it is anticipated to reveal pozzolan reaction ability by heat-treatment. To find out pozzolan reaction ability of discarded Bentonite slurry by heat-treatment, the experiment is excuted Phenolphtalein test, setting test, pH test and the analysis by X-ray diffractor. As a result of this study, discarded Bentonite slurry can be utilized as concrete mineral admixture by heat-treatment and especially, pozzolan reaction ability of discarded Bentonite slurry is superior to the situation of 50$0^{\circ}C$~$700^{\circ}C$, 60min.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.43-44
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• 2016

Large amount of dredged sea soil is produced in southeast seashore region in during harbor maintenance. Disposal of dredged sea soil has become difficult due to the environmental regulation. Therefore, disposal of dredged sea soil method is to landfill. But, the capacity of the landfill limit state and if the size of the dredged sea soil is in the range of silt or clay, it cannot be used as reclamation material because ground subsidence occur. In this study, analyzed the pozzolanic activity of dredged sea soil. Analysis of the results showed a pozzolanic activity of dredged sea soil. In addition, incorporation of heat treated dredged sea soil increase both 28 and 56 day compressive strength of mortar specimen.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.32-33
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• 2016

In this work, pozzolanic activities of various waste materials were compared with those of well-known pozzolanic materials. Uncondensed and densified silica fume, two ASTM class F fly ashes with different calcium contents, and bentonite powder, ceramic powder obtained from wash basin, and waste glass wool, which can possibly possess pozzolanic property were chosen for comparison. Drop in electrical conductivity at 40℃ saturated lime solution was measured for each materials. The amount of Ca(OH)₂ decomposed from cement paste at 450~500℃ was also measured used to evaluate pozzolanic activity. The 28 day compressive strength were used to observe the mechanical property enhanced by various waste materials.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.162-163
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• 2015

A borosilicate glass was powdered to incorporation into the cement for the purpose of improving the neutron shielding performance of concrete. The particle size of the borosilicate glass powder was prepared by a similar to that of cement. 50×50×50mm size of cube specimens were measured a compressive strength. As a result, compressive strength of 10% borosilicate glass powder replaced specimens were improved than that of plain specimens.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.49-50
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• 2014

Dredged sea soil contains various contaminants. First priority to recycle dredged sea soil is to pretreat it to remove various contaminants because recycling dredge sea soil without any pre-treatment may cause a secondary contamination due to the leaching of hazardous chemicals. In this study, pretreated dredged sea soil was used to investigate pozzolanic activity. The properties of pretreated dredged sea soil were investigated, the method for heat treatment was determined, and the compressive strength of mortar using dredged sea soil was examined to evaluate pozzolanic activity. According to the results, pretreated dredged sea soil has some possibility to work as a pozzolanic material. When dredged sea soil was heat treated for 90min at 550℃, compressive strength was shown to be comparable to that of plain cement mortar.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.265-273
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• 2009

There have been numerous studies to develop eco-friendly concrete. The attempt to reduce the amount of cement used is suggested as one of the solutions for eco-friendly concrete. To decrease the usage of cement, the pozzolan reaction materials are used as a mineral admixture. Hwang-toh, which is broadly deposited in Korea is a well known environment friendly material and the activated hwang-toh, which has the property of pozzolan reaction, is alternatively used as a mineral admixture of concrete. The purpose of this study is to investigate the drying shrinkage of hwang-toh concrete mixed with recycled PET fiber. Therefore, drying shrinkage experiments are performed to analyze mechanical property of hwang-toh concrete mixed with recycled PET fiber. Test results showed that the drying shrinkage is controlled by hwang-toh admixture and PET fiber.