• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.47-53
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• 2010

The purpose of this study was to investigate the effectiveness of a stabilization treatment for As contaminated soil. A combination of hydrated lime, Portland cement, $FeCl_3{\cdot}6H_2O$, and NaOH were used as stabilizing agents. The effectiveness of stabilization treatment was evaluated by the Korean Standard Test (KST) method (1N HCl extraction). Sequential extractions were performed to investigate the As distribution after treatment. Following the application of the treatment, curing periods of up to 7 and 28days were investigated. The experimental results showed that a combination of hydrated lime/Portland cement was more effective than treatments of hydrated lime or Portland cement at immobilizing As in the contaminated soil. The treatment of 25wt% hydrated lime and 5wt% Portland cement was effective in reducing As leachability less than the Korean warning standard of 20 mg/kg. However, the treatments of hydrated lime and Portland cement failed to meet the Korean warning standard even when up to 30 wt% was used. The treatment utilizing hydrated lime and $FeCl_3{\cdot}6H_2O$ was not effective in properly reducing As leachability. The addition of $FeCl_3{\cdot}6H_2O$ was negative in terms of pH condition. Moreover, the treatment with hydrated lime/NaOH was effective in reducing As leachability but not as much as hydrated lime/Portland cement. The sequential extraction results indicated that the residual phase was greatly increased upon the treatment of hydrated lime/Portland cement. It was concluded that the hydrated lime/Portland cement treatment was the best among the other combinations studied at achieving trace As concentrations.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.11-16
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• 2002

The production of Portland cement involves maximum use of resources and energy, which leads to destruction of tile ecological environment, raising in serious environmental issues such as acid rain and the greenhouse effect. In order to combat the arising problems associated with Portland cement, it thus is necessary that a non-clinker cement should be developed. In this study, non-clinker cement is produced by blending granulate blast furnace slag with phosphogypsum as main materials, and small amounts of hydrate lime or waste lime as activators. This paper aims to investigate compressive strength according to various condition of mixing ratio, blame, W/C ratio and curing temperature. Compressive strength of non-clinker cement increases continuously according to increase in curing age and blain. Although the compressive strength is fairly comparable to that of OPC in the early curing age, it reaches a higher lever in the later age than that of OPC due to the optimum mixing ratio and the continuous reaction of slag and phosphogypsum. Results obtained from this study have shown that non-clinker cement could be used as a replacement of OPC.

• Geomechanics and Engineering
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• v.8 no.1
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• pp.17-31
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• 2015

An experimental program was performed to study the effects of cement stabilization on the geotechnical characteristics of sandy soils. Stabilizing agent included lime Portland cement, and was added in percentages of 2.5, 5 and 7.5% by dry weight of the soils. An analysis of the mechanical behavior of the soil is performed from the interpretation of results from unconfined compression tests and direct shear tests. Cylindrical and cube samples were prepared at optimum moisture content and maximum dry unit weight for unconfined compression and direct shear tests, respectively. Samples were cured for 7, 14 and 28 days after which they were tested. Based on the experimental investigations, the utilization of cemented specimens increased strength parameters, reduced displacement at failure, and changed soil behavior to a noticeable brittle behavior.

• Journal of the Mineralogical Society of Korea
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• v.18 no.4 s.46
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• pp.301-312
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• 2005

The present study investigated the physical changes and reaction products with setting time after mixing of various mineral admixtures such as lime, hydrated lime, gypsum, kaolin, zeolite and diatomaceous earth with four types of cement (portland cement, slag cement, quick lime, hydrated lime) and clay rich sediments in soft foundation. As results, slag cement showed the greater compressive strength than normal portland cement. The mixing experiments with various mineral admixtures and slag cement resulted that gypsum showed the greatest compressive strength. Additionally, we conducted mixing experiments with various mixing ratios of gypsum and slag cement. The experiments showed that the mixing ratio of $30\%$ gypum and $70\%$ slag cement has the greatest compressive strength. Ettringite was produced as a reaction Product. This fact indicates that gypsum effectively promotes hydration reaction and contributed to the greater compressive strength. These experimental results can be used as fundamental data for the stabilization of soft clay foundation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.108-112
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• 2005

In this research, the physical properties of fresh concrete using lime stone powder as a part of cement were investigated. Fresh concrete using lime stone powder was prepared with various lime stone powder replacement($5{\sim}12$ volume %) for cement and the quantities of sand aggregate ratio in concrete were 47.3%, 48.5% and 49.4% of ratio of sand aggregate. The workability, flowing characteristics, air content and bleeding of concrete using lime stone powder were tested and the results were compared with those of ordinary portland cement concrete. In the experiment, we acquired satisfactory results at the point of fresh concrete characteristics using lime stone powder within the replacement ratio of $8{\sim}12%$ and the optimum quantity of sand aggregate ratio in concrete was found to be $48.5%{\sim}50%$ of ratio of sand aggregate.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.1
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• pp.9-19
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• 1998

A laboratory study was conducted to investigate the immobilization of the laboratory waste sludge, mainly from chemical oxygen demand (COD) waste, using cementitious binders. The binders were: Ordinary Portland Cement (OPC), and lime-Rice Husk Ash(RHA) cement. The economic evaluation was done for three different kinds of cementitious binders, namely, OPC, Portalnd Rice Husk Ash Cement (PRHAC) which contained rice husk ash 50 percent by dry weight, and lime-RHA cement. The result showed that lime-RHA cement was the cheapest. The applicability of Freundlich's desorption isotherm was studied to assess the teachability of sludges. The teachability of cement mortars was found to follow the desorption isotherms. Therefore, it was concluded that based on this test, the leachate concentrations of the solidified heavy metals could be predicted, approximately by the Freundlich's isotherm desorption modeling.

• Journal of Environmental Science International
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• v.2 no.1
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• pp.9.2-19
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• 1993

A laboratory study was conducted to investigate the immobilization of the laboratory waste sludge, mainly from chemical oxygen demand (COD) waste, using cementitious binders. The binders were: Ordinary Portland Cement (OPC), and lime-Rice Husk Ash (RHA) cement. The economic evaluation was done for three different kinds of cementitious binders, namely, OPC, Portaind Rice Husk Ash Cement (PRHAC) which contained rice husk ash U percent by dry weight, and lime-RHA cement. The result showed that lime-RHA cement was the cheapest. The applicability of Freundlich's desorption isotherm was studied to assess the teachability of sludges. The teachability of cement mortars was found to follow the desorption isotherms. Therefore, it was concluded that based on this test, the leachate concentrations of the solidified heavy metals could be predicted, approximately by the Freundlich's isotherm desorption modeling.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.584-587
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• 2004

This research investigates the rheological behavior and the confined water ratio of the cement paste and binder condition in order to predict mix design proportion of the high flowing concrete. The purpose of this study is to determine the optimum replacement ratio of binders including fly ash, and lime stone powder by the cement weight. For this purpose, belite cement, blast furnace slag cement and ordinary portland cement are selected. As test results, the confined water ratio shows the following range ; OPC>blast furnace slag cement>belite cement. Therefore, belite cement is proved very excellent cementitious materials in a view point of the flowability. The optimum replacement ratio of lime stone powder is shown over $30\%$ in case of belite cement and about $10\%$ in case of slag cement type. Also, the optimum replacement ratio of fly ash is shown $30\%$ by the cement weight considering the confined water ratio and deformable coefficient of the paste condition.

• KIEAE Journal
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• v.10 no.2
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• pp.3-8
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• 2010

Many countermeasures are presented to make excessive earth circumstance pollution better in the earth. A lot of researches are in progress to lessen $CO_2$ among the industries exhausting it. The industries manufacturing cement are making many countermeasures. Many concernments on ECO-friendly materials, rather than cement, are increased, and researches are in progress to develop them. Lime, material mostly used before Portland cement appeared, attracts the Occident as well as the Orient. In the Occident, lime mortar was used in common, for maintaining and repairing cultural properties, too. This study is aimed at offering basic materials for the modern use of lime, ECO-friendly material. This study measured the change of intensity and weight with lime, sand, and earth, basic materials of Samhoimool. As a result, at the beginning, hydrated lime displayed its density late, but as time was gone, density was promoted continuously. In addition, density was promoted, when it was given heat at the beginning. If heat-generation reaction of quicklime and water was used, density was promoted at the beginning, but liquidity showed a drop.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.702-708
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• 2003

Cement paste, mortar or concrete specimens, substituting the content of Portland cement with fly ash up to 50 wt%, were prepared to investigate the effect of fly ash on the temperature, free lime content and strength etc. of mortar/concrete. Being compared with the concrete made of ordinary Portland cement, temperature increment of the concrete containing 50 wt% fly ash reduced, according to appropriate conversion formulae, to about 45％ at the 7 days curing time: the temperature increment of the former amounted to 33.4$^{\circ}C$, while that of the latter only to 18.7$^{\circ}C$. On the other hand, it is better to control the content of fly ash in the cement that is used for reinforced concrete not to exceed 30 wt％. In this study, more than 28 days curing time is necessary in order that the strength of concrete made of fly ash cement will be higher than that of pure Portland cement. In addition, 28-days concrete strength higher than 360 kg/$\textrm{cm}^2$ could be easily achieved even with 50 wt% fly ash cement.