• Journal of the Korean GEO-environmental Society
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• v.12 no.4
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• pp.17-24
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• 2011

For the purpose of cut off and ground stabilization, water glass chemical grouting method using sodium silicate has problems of weakening durability and ground water pollution because leaching was conducted when the homogel is exposed to the ground water as time elapses. The purpose of this study is to identify the effect of alkali silica sol ground injection materials, it was compared with the sodium silicate ground injection materials using water glasses. For sodium silicate and alkali silica sol by mixing each case is divided into four different specimens were made and tested. The characteristic of alkali silica sol ground injection material was analyzed by unconfined compression test and environmental impact statement of ordinary portland cement and blast furnace slag cement. Alkali silica sol specimens were made mixing A-solution and B-solution in the proportion of one on one. Through this study, alkali silica sol ground injection mixing blast furnace slag cement has excellent strength and environment-friendly.

• Journal of the Korean GEO-environmental Society
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• v.11 no.9
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• pp.47-53
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• 2010

This study was made on the fact that the compressive strength characteristic of the recently developed alkali silica-sol chemical grout material was examined, whose grout material used for this study was designed to understand its strength property through the uniaxial compressive strength test(homo-gel, sand-gel), permeability test, deflection strength test, etc. In order to compare with the engineering characteristics regarding alkali silica-sol grout material and sodium silicate grout material. The uniaxial compressive strength of silica-sol grout material was identified to be increased more than 3~5 times than sodium silicate grout material at the early stage(within 72 hours). When comparing with the uniaxial compressive strengths of Sand-gel and Homo-gel at the material age of 28 days in case of silica-sol grouting material the strength of Sand-gel was measured to be about 1.3 times higher than Homo-gel. In case of silica-sol, it is assumed to have the property to exert high strength when it is actually grouted into the ground. As a result of permeability test it is judged that it is possible to apply the silica-sol to the site in the place requiring the water cut-off as the silica-sol. As a result of testing the strength at the material age of 28 days of grouting-use silica-sol showed more than 3 times' difference than the sodium silicate grouting material.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.631-635
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• 2011

Spherical and non-spherical silica particles prepared by the direct oxidation were studied for the effect of the particle size and shape of these particles on oxide CMP removal rate. Spherical silica particles, which have 10~100 nm in size, were prepared by the direct oxidation process from silicon in the presence of alkali catalyst. The 10 nm silica particles were aggregated by addition of an acid, an alcohol, or a silane as an aggregation inducer between the particles. Two or more aggregated silica particles were used as a seed to grow non spherical silica particles in the direct oxidation process of silicon in the presence of alkali catalyst. The oxide removal rate of spherical silica particles increased with increasing an average particle size for spherical silica abrasives in the oxide CMP. It further increased non-spherical particles, compared with the spherical particles in the similar average particle size.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.715-722
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• 2019

The durability of concrete structures deteriorates due to the corrosion of rebars and concrete deterioration by harmful ions (CO₃^2-, Cl^-, SO₄^2-) penetrating and diffusing from the outside into concrete. Therefore, the use of surface-protection finishing mortar is very important for preventing or delaying the deterioration of concrete. In this study, the possibility of the prevention of deterioration or delay of deterioration of concrete was investigated using natural latex modified with silica sol and calcium ions for cement mortar, which can be used to repair the mortar of deteriorated concrete or for finishing the mortar of concrete. As a result, fine calcium silicate hydrate was formed in the pores of the cement material due to the calcium ions and silica sol components contained in the modified latex component that reduce the pore distribution of the cement mortar, thereby reducing the penetration and diffusion of harmful ions (CO₃^2-, Cl^-, and SO₄^2-). Furthermore, the latex component was found to be present in the pores of the cement to improve the alkali resistance and carbonation resistance.

• Advances in nano research
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• v.4 no.3
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• pp.181-195
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• 2016

Addition of nano-$SiO_2$ (NS) to geopolymer composites has been studied through measurement of compressive strengths, FTIR and XRD analysis. Alumino-silicate materials are coarse aggregate included waste concrete and demolished walls with its cementing binder, cement kiln dust (CKD) used and can possess a pronouncing activation for the geopolymer reaction resulting from the high alkali contents within. Materials prepared at water/binder ratios in a range of 0.30: 0.40 under curing of $40^{\circ}C$ and 100% Relative Humidity (R.H.), while the used activator is sodium hydroxide in the ratio of 2 wt. %. First, CKD is added in the ratio from 10 up to 50 wt., %, and the demolished walls was varied depending on the used CKD content, while using constant ratio of waste concrete (40 wt., %). Second step, depending on the optimum CKD ratio resulted from the first one (40 wt. %), so the control geopolymer mix composed of cement kiln dust, demolished walls and waste concrete in the ratio (40:20:40, wt %). Nano-silica partially replaced waste concrete by 1 up to 8%. Results indicated that, compressive strengths of geopolymer mixes incorporating nano-silica were obviously higher than those control one, especially at early ages and specially with 3%NS.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.3
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• pp.171-177
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• 2007

This study suggested a new method to stabilize molten salt wastes generated from the pyre-process for the spent fuel treatment. Using conventional sol-gel process, $SiO_2-Al_2O_3-P_2O_5$ (SAP) inorganic material that is reactive to metal chlorides were prepared. In this paper, the reactivity of SAP with the metal chlorides at $650{\sim}850$, the thermal stability of reaction products and their leach-resistance under the PCT-A test method were investigated. Alkali metal chlorides were converted into metal aluminosilicate($LixAlxSi1-_xO_{2-x}$) and metal phosphate($Li_3PO_4\;and\;Cs_2AlP_3O_{10}$) While alkali earth and rare earth chlorides were changed into only metal phosphates ($Sr_5(PO_4)_3Cl\;and\;CePO_4$). The conversion rate was about $96{\sim}99%$ at a salt waste/SAP weight ratio of 0.5 and a weight loss up to $1100^{\circ}C$ measured by thermogravimetric analysis were below 1wt%. The leach rates of Cs and Sr under the PCT-A test condition were about $10^{-2}g/m^2\;day\;and\;10^{-4}g/m^2\;day$. From these results, it could be concluded that SAP can be considered as an effective stabilizer for metal chlorides and the method using SAP will give a chance to reduce the volume of salt wasteform for the final disposal through further researches.