• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.297-304
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• 2002

This study is about penetrability of Micro Cement(MC) used for ground improvement. In this study, the characteristics of chemical grouting such as solidification, penetrability were analyzed experimentally by changing permeability of ground, grain size and relative density of grout material. For evaluating applicability of grout material, solidification test and penetrability test were performed. From the results of the tests, effective solidification ratio and penetrability ratio of MC was each 75%, 86% to be excellent when ground permeability was in the range of 10$^{-2}$ and 10$^{-4}$ cm/sec. Otherwise, those of Ordinary Portland Cement(OPC) were both lower than 50% to be poor. When penetrability of grout material is needed for improvement of dam foundation and soft ground, application of MC Is much superior to that of the other materials. The results of the grouting tests in the water flowing ground show that solidification effect of long gel-time grout material is excellent as injection pressure increases when groundwater velocity is relatively low. But when groundwater velocity is relatively high, solidification effect of long gel-time grout material is very poor because most grout materials are outflowed. Therefore, as groundwater velocity is high, effective solidification ratio of long gel-time grout material is better than that of short gel-time grout material, also penetration distance of long gel-time grout material is longer than that of short gel-time grout material.

• Journal of the Korea Concrete Institute
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• v.11 no.4
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• pp.31-41
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• 1999

Blended Low Heat type cement is ground granulated blast furnace slag and fly ash mixed ternary with ordinary portland cement. From the viewpoint of X-ray patterns of domestic LHC, the main components of cement such as $C_2$S, $C_3$A, $C_3$S are considerably reduced. Therefore the heat evolution of LHC paste is 42cal/g lower than of OPC paste. At early age, the compressive strength development of LHC concrete is delayed, but the slump loss ratio of fresh concrete is reduced more than 20% with elapsed time. The penetrability of LHC is lower than that of OPC by 1/7.8 with the penetrability of chloride ion into the concrete until the age of 120 days. And the PD Index value of LHC is 0.44$\times$10-6 $\textrm{cm}^2$/s, which indicates only 39.3% of OPC. From the Mercury Intrusion Porosimetry test of cement past, we know that the pore size of LHC is more dense than that of OPC by production of C-S-H.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.229-236
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• 2002

In this study, the characteristics of chemical grouting, such as solidification, penetrability, were analyzed experimentally by grain size of grout materials and permeability, relative density of the ground. For evaluating applicability of grout material, solidification tests and permeability tests were peformed. From the results of the tests, effective solidification ratio and penetrability ratio of Micro Cement were 75% and 86% respectively when ground permeability was in the range of 10$^{-4}$ to 10$^{-2}$cm/sec. On the other hand, effective solidification ratio and penetrability ratio of Ordinary Portland Cement (OPC) were both lower than 50%. When penetrability of grout material is needed for improvement of dam foundation and soft ground, application of Micro Cement is much superior to that of the other materials. The results of the grouting tests in the hydrodynamic ground show that the solidification effect of long gel-time grout material is excellent as injection pressure increases when groundwater velocity is relatively low. But when groundwater velocity is relatively high, the solidifcation effect of long gel-time grout material is very poor because most grout materials are outflowed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.253-254
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• 2022

In this study, catechol-functionalized chitosan (Cat-Chit), a well-known bioinspired polymer that imitates the basic structures and functions of living organisms and biological materials in nature, was synthesized and combined with cement mortar in various proportions. The compressive strength, tensile strength, drying shrinkage, accelerated carbonation depth, and chloride-ion penetrability of these mixes were then evaluated. In the ultraviolet-visible spectra, a maximum absorption peak appeared at 280 nm, corresponding to catechol conjugation. The sample containing 7.5% Cat-Chit polymer in water (CPW) exhibited the highest compressive strength, and its 28-day compressive strength was ~20.2% higher than that of a control sample with no added polymer. The tensile strength of the samples containing 5% or more CPW was ~2.3-11.5% higher than that of the control sample. Additionally, all the Cat-Chit polymer mixtures exhibited lower carbonation depths than compared to the control sample. The total charge passing through the samples decreased as the amount of CPW increased. Thus, incorporating this polymer effectively improved the mechanical properties, carbonation resistance, and chloride-ion penetration resistance of cement mortar.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.229-230
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• 2011

We could see that, the thinner the retaining wall is, the more advantageous Premixed Agent Type Waterproof method is in the aspect of economic efficiency. The reason is because, in the case of Premixed Agent Type Waterproof method, the thicker the retaining wall is, the higher the construction cost increases due to increase in the material quantity required which increases in proportion to the area in the case of Premixed Agent Type Waterproof method. We could see that, the thinner the retaining wall is, the more inferior the economic efficiency of Infiltration Type Waterproof method is to that of Premixed Agent Type Waterproof method, as, in the case of Infiltration Type Waterproof method, the quantity of material required is fixed in proportion to the area. Consequently, we concluded that Premixed Agent Type Waterproof method is economically advantageous up to the wall thickness of 700 mm and Infiltration Type Waterproof from 800 mm.

• Journal of the Korean GEO-environmental Society
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• v.8 no.2
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• pp.57-63
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• 2007

Coal combustion by-product (CCB) bottom ash, obtained from burning of pulverized coal, has physical properties which are similar to that of natural sand with particle sizes ranging from fine gravel to fine sand. Several studies have been completed to utilize pulverized coal combustion (PCC) bottom ash as a partial or full replacement of fine aggregate in cement concrete products. The objectives of this study were to develop air-entrained concrete composites using PCC bottom ash from burning of Illinois coal and to demonstrate the use of these composites on real-world projects. The results obtained show that the compressive, splitting-tensile, and flexural strengths of concrete composites is slightly lower than that of conventional concrete are early curing ages. However, after 60 days of curing, the strength of concrete composites is either equal to or slightly higher than that of an equivalent conventional concrete. The concrete composites showed lower resistance to chloride ion penetrability than that of an equivalent conventional concrete at early curing ages. However, after 28 days of curing, concrete composites showed better resistance to chloride ion penetrability compared to that of an equivalent conventional concrete.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.39-47
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• 2002

This study was carried out in order to produce useful material for the forest multiple use and forest protection by soil physico-chemical analysis of studied area in Mt. Palgong. The results of soil physico-chemical analysis and statistical analysis represented as following 2 points. 1. Soil depth was in the range of average 61.1 cm and soil texture was loamy sand and sandy loam except Donghwasa area. The part of solid phase and gaseous phase were higher than other areas, but liquid phase was less in verse. Soil water content was in an average 49.5%, penetrability was average $1.95{\times}E^{-2}cm/sec$ and the average of soil hardness was $1.64Kg/cm^2$. This data showed that soil water content, penetrability and soil hardness were good at Mt. Palgong forest soils. 2. Soil pH was the range of 3.4 to 6.0, organic carbon content was 2.8% that is nearly mean of the Korea brown forest soils, total N content is somewhat smaller than that of other places, and total average C/N ratios was 13.9. Average available $P_2O_5$ concentration was 5.05 mg/kg that is lower than that of any others. The concentration of available P of coniferous forests is higher than that of deciduous forests. Exchangeable cations content is similar to those of the Korea brown forest soil and the order of the cation content extent is $Ca^{2+}$ > $Mg^{2+}$ > $Na^+$ > $K^+$.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.1
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• pp.12-17
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• 1984

In order to find out the effects of soil conditioner treatment on the water movement in sandy loam and silt loam soils were treated with two different kinds of soil conditioners, hydrophobic Bitumen 0.4% or hydrophillic Uresol 0.6%, and the changes of wetting angle (soil-water contact angle), penetrability and diffusivity were measured. The results were summarized as follows: 1. Uresol 0.6% treatment decreased the wetting angle of sandy loam more than $10^{\circ}$, but there was no big difference in silt loam. 2. Sandy loam soil was changed to almost hydrophobic and the wetting angle of silt loam soil was increased to $84.9^{\circ}$ as compared to $76.0^{\circ}$ of untreated soil by Bitumen 0.4% treatment. 3. By Uresol treatment, penetrability of sandy loam was doubled but there was not difference in silt loam, and it was decreased to half in two soils by Bitumen treatment. 4. A significant positive correlation between penetrability and the cosine of wetting angle was recognized. 5. Soil water diffusivity was greatly changed by soil conditioner treatment, and the big differences were appeared at lower soil moisture content.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.249-255
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• 1995

This study was conducted to investigate the effects of some soil conditioners, such as polyacrylamide(PAM), polyvinylalcohol(PVA) and Bitumen emulsion, on aggregate formation and stability, wetting angle, sorptivity and penetrability of the soil with different textures : sand, sandy loam, loam and clay loam. A pot experiment was carried out to find out the effect of treatment on the germination and growth of lettuce with three textures : sand, sandy loam and silt loam. Soil aggregates larger than 2mm in untreated soils at dry condition were naught in sand, 45% in sandy loam, 80% in loam and 90% in clay loam. Treatments of soil conditioners tended to increase the occurrence of soil aggregate larger than 2mm, which were 20~25% in sand, 55~75% sandy loam, but not affected greatly aggragate occurence in loam and clay loam. The aggregate instability was decreased by the soil conditioner treatment. The wetting angles of the soils were greatly changed by hydrophobic of Bitumen, but those were changed slightly by PVA and PAM application. The sorptivity and penetrability data indicated that the effects of different materials on these parameters differed depending upon soil texture. Application of PVA and PAM were no effect exceptive in sand. Application of Bitumen revealed that water movement was not showed in all soils. The germination rate, root weight and top plant weight of lettuce were increased in all soils by PAM treatment as compared to untreated soils. Particularly the greater effect was occurred in sand soil than in sandy loam and silt loam. PAM increased greatly the moisture content and air phase of soils.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.60-65
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• 1995

Recently, water-proof treatments have been required for reducing the carbonigation in the upper plate of bridge. In this study, the experiments were conducted for penetrable water proof in two ways ; one is under natural conditions and the other under artificial. The experimental results shows that the penetrable depth for the penetrable water proof shows in inverse proportional to concrete strength and auti-acid property. Also, auti-heating property is revealed excellent with the penetrable water proof and endurability under the disclosure in natural condition is not permanent