• Journal of the Korean GEO-environmental Society
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• v.12 no.12
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• pp.71-78
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• 2011

This paper aims to present the evaluation of engineering characteristics and reusing possibility of waste powders produced in dolomite and limestone nonmetal mining by physical and mechanical experiments on compaction, uniaxial compressive strength, permeability, chemical composition, and so on. Granite soil, 2 types of limestone waste powder, and 1 type of dolomite waste powder were used for main materials, and cement and bentonite were used for admixed materials in this experiments. The findings based on the experimental results are the severe difference of chemical composition of the dolomite & limestone waste powder and the crushed rock waste powder, and the outstanding of engineering characteristics of the dolomite waste powder with high content of MgO compared with the limestone waste powder. The engineering properties on compaction, uniaxial compressive strength, and permeability are enhanced with increase of admixed ratio of waste powder on granite soil. From the experimental results, it can be suggested that the dolomite waste powder admixed with in-situ granite soil is useful as geo-materials with considering of distribution costs.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.139-144
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• 2000

This study was conducted to obtain the basic information to increase the practical use of soil survey data through the subdividing of valley shapes with soil sequences due to different parent rocks, and to study the relationship between the valley shapes and parent rock. The various rocks such as sedimentary(gray shale and sand stone) and igneous rocks(granite, granite gneiss and andesite porphyry) which are the major parent rocks in Yeongnam area were investigated. The characteristics of valleys formed and the kinds of soils derived from different rocks were analysed by using aerial photographs and topographical maps scaled 1:5,000. The rill density in igneous rock area was as high as 40. But the rill bifurcation ratio of first order stream was higher in the sedimentary than the igneous rocks except granite area. The mean slope of valleys in igneous areas was about 8%, which was higher than that of the sedimentary areas. The variability of valley width in the complexly metamorphosed rock, such as granite gneiss, and andesite porphyry, was greater than in sedimentary and in granite rocks. Based on the variability of valley widths and valley slopes, it was possible to classify the valleys into two types. The "Uterus-shaped valleys" had wide variability of valley width and were located in the areas of granite gneiss and andesite porphry rocks. while the "Roots-shaped valleys" had narrow variability of valley width and were located in the sedimentary areas. "Uterus-shaped valleys" were typified by having land forms of mountain foot slopes and alluvial fans, and the soil drainage sequences also had complexities. So that, we concluded that the variability of valley width and valley slopes was associated with kinds of parent rocks and metamorphism which influences soil sequence and characteristics.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.449-456
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• 2013

This study was carried out to assess the suitability in terms of the standards of material quality of basalt aggregates from JEJU Island as a source for concrete aggregate. Quality assessments on the basalt aggregates were performed to assess the soundness of coarse aggregates using sodium sulfate solution, aggregate crushing test, and Los Angeles abrasion test. In addition, XRD, XRF, porosity, and compressive and tensile strength tests were performed to analyze the chemical components and the mechanical properties. In general, the mechanical properties of basalt aggregates from some areas did not meet the Korea Standards (KS), but the levels of compressive and tensile strength were higher than those of granite, andesite, and sandstone of other regions.

• 보존과학연구
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• s.29
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• pp.149-162
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• 2008

Because stone cultural heritages in Korea are mostly situated outdoors without any notable protection, there are severe damages from physical, chemical and biological weathering. And this in turn causes deformation and structural damage. To counteract this problem and increase durability, various kinds of conservation materials are used in the conservation and restoration treatment. However, there are not many practical and technological experiments on this subject. Accordingly this research is for analysis of effect for treatment to make use a resin of the ethyl silicate for the granite in Mt. Nam of Gyeongju. It takes a long time to confirm the test result regarding durability and side effects of the conservatives after treatment. So we built up an artificial environment through freezing and melting test, and evaluated the conservation materials. As a result of this experiment, porosity and absorptivity was increased in accordance with processing of freezing and melting test. But other things such as elastic wave speed, elastic modulus, uniaxial compressive strength and tensile strength was decreased. It will make a plan to form a method of research systematically for mechanism and element of weathering and to elicit a correlation among experiment of artificial weathering and practical natural weathering from next research.

• Geotechnical Engineering
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• v.14 no.1
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• pp.49-58
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• 1998

It was investigated whether the scrap tire can be recycled as a construction material for controlling the frost heave of the ground. Some frost heave tests and a frost penetration depth test in the laboratory were performed on the weathered granite soil mitred with variable amount of scrap tire powder under the atmospheric temperature at -$17^{\circ}$ to find the basic effects of the scrap tire on the control of frost. The frost heave control layer of the crushed stone mixed with scrap tire chips directly below thin subbass in the bituminous pavement was found to be effective for practical use. And the equation for the required thickness of this frost heave control layer with freezing index was suggested.

• Journal of Conservation Science
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• v.25 no.1
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• pp.25-38
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• 2009

The Gyeongju Seokbinggo (Treasure No. 66) is an ice-storing stone warehouse, consisting mainly of alkaligranite which shows milky white color and medium-grained textures with drusy cavities. As results of deterioration assessment, the deterioration rates were determined as crack (12.5%), disjoining (6.7%), breaking-out (25.1%), exfoliation (20.9%), efflorescence (6.5%), brown discoloration (9.8%), darkgray discoloration (2.0%) and biological discoloration (36.5%). Comprehensive physical deterioration rate and discoloration rate were calculated as 43.7% and 68.7%, respectively, that indicates the Seokbinggo has been severely weathered. Indoor relative humidity was above 90% except in winter season. Indoor microclimate was hardly fluctuating although indoor microclimate was dependent on the outdoor climate. The main cause of deterioration was high relative humidity and a long time of wetness due to penetration of rain, underground water and condensation. It was identified that the water brought out biological discoloration, dissolution of minerals, structural movement and efflorescence, and the dust from the ground soil in front of the entrance accelerated brown and dark gray discoloration on the stone surface.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.555-568
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• 2004

The demand of aggregate resources in Korea has been increased with a rapid economic growth since the 1980s. About 25% of the total aggregate production is derived from riverine aggregates, 20% to 25% from marine sands, 40% to 45% from crushed aggregate and the rest 5% to 15% from old fluvial deposits. The abundance of crushed coarse aggregates varies in the uniform distribution of country, but in general it can be concentrated in the most densely populated areas, five main cities. Typical rock types of the Korean crushed stones are classified as plutonic rocks of 27%, metamorphic rocks of 32%, sedimentary rocks and volcanic rocks of 18%, respectively. The most abundant coarse aggregate used in the country is obtained from granite (25% of total) and subordinately gneiss (20%), sandstone (10%) and andesite (10%). Although rock types using as dimension stone are only fifteen, those as aggregate amount up to twenty nine rocks. These rocks consist of plutonic rocks such as granite, syenite, diorite, aplite, porphyry, felsite. dike and volcanic rocks such as rhyolite, andesite, trachyte, basalt, tuff, volcanic breccia and metamorphic rocks such as gneiss, schist, phyllite, slate, meld-sandstone, quartzite, hornfels, calc-silicate rock, amphibolite. And sandstone, shale, mudstone, conglomerate, limestone, breccia, chert are main aggregate sources in tile sedimentary rocks. The abundance of plutonic rocks is the highest in Chungcheongbuk-do, and decreases as the order of Jeollabuk-do, Gangwon-do and Gyeonggi-do. In Jeollanam-do, volcanic aggregates occupy above 50%, on the contrary sedimentary aggregates are above 50% in Gyeongsangnam-do.

• Journal of the Korean earth science society
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• v.33 no.2
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• pp.126-138
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• 2012

Ultrasonic method is widely used for the evaluation of weathering index and of degree of deterioration because it is easily applicable $in$ $situ$. The basic idea of the method is that the ultrasonic velocity decreases as a rock is being weathered. Thus, the difference of ultrasonic velocities between fresh rock and weathered rock indicates the degree of weathering. In this method, the ultrasonic velocity of fresh rock is assumed to be 5,000 m/s. However, this assumption can cause significant errors in estimating weathering index, especially in case that those rocks of the same type have a wide range of ultrasonic velocities such as in Korea. Therefore, we obtained twenty rock specimens and sixty core samples commonly used for stone cultural heritages in Korea, and measured ultrasonic velocities. From the results, we found that the ultrasonic velocities of the same rock type, granite samples range from 3,118 to 5,380 m/s, and that the estimated weathering index can be highly biased if we use the fixed value of 5,000 m/s. We created a database (DB) by combining the measurement data and reported it. We also measured ultrasonic velocities by direct and indirect methods to quantify the calibration coefficient for each sampling site. We found that the calibration coefficients vary widely from site to site (1.31-1.76). Other factors, such as operator bias and temperature did not show any significant effect on errors in ultrasonic velocity measurements. Lastly, we applied our ultrasonic velocity DB and calibration coefficients to a stone cultural heritage, Bonghwang-ri Buddha statue. Our estimation of the weathering index was 0.3, 0.1 smaller than that by conventional method. The degree of deterioration was also different, "moderately weathered", while conventional method gave "highly weathered". Since other independent studies reported that the degree of deterioration of the Buddha statue was "moderately weathered", our estimation seems to be more accurate. Thus our method can help accurately evaluate the weathering index and the conservation planning for a stone cultural heritage.

• Conservation Science in Museum
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• v.19
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• pp.1-18
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• 2018

The Stele for National Preceptor Hongbeop from the Jeongtosa Temple site in Chungju is one of the most important stone cultural heritage items for exemplifying the style of the Goryeo era. Despite its obvious value, this relic has been stored in a weathered condition at the National Museum of Korea. It had suffered various dismantling and displacements during the Japanese colonial period and had long been exposed in the open air. The stele was selected as a subject for the Stone Monuments Restoration Project launched by the National Museum of Korea in 2015. In preparation for its outdoor exhibition as part of the restoration project, this study investigated the characteristics of its materials, produced a map of its deterioration from weathering, and carried out ultrasonic analysis of the materials to provide findings useful for conservation treatment. The materials analysis revealed that the turtle-shaped pedestal of the stele was made from two-mica granite consisting of medium-grained quartz, plagioclase, alkali feldspar, biotite, and muscovite. Its body stone is crystalline marble, the rock-forming mineral in which is medium-grained calcite in a rose-pink color with dark grey spots. The dragon top of the stele is made of crystalline marble, the major component of which is medium-grained calcite of a light-grey color. The deterioration consists of 21.5% abrasion on the stone body, with its south face most damaged, and 18.6% granular disintegration, with the north face most damaged. The ultrasonic material characterization conducted for mapping the general condition of weathering shows low values on the parts-assembly area of the turtle-shaped pedestal and on the upper portion of the stone body. It is considered that there is dislocation due to partial blistering and fracturing as well as to the differences in surface treatment. Prior to the outdoor exhibition of the stele, the surface was cleaned of contaminants and was consolidated based on the scientific investigation in order to prevent weathering from the external environment.

• Journal of Conservation Science
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• v.27 no.4
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• pp.431-440
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• 2011

The thermal expansion coefficient of epoxy/inorganic additives composites was controlled by changing the amount of the inorganic additives such as talc and fused silica. The epoxy resin comprises hydrogenated bisphenol A (HBA)-based epoxide, difunctional polyglycidyl epoxide (DPE) as a diluent and isophorone-diamine (IPDA) as a crosslinking agent, which was subsequently mixed with inorganic additives (talc and fused silica). The thermal expansion coefficient was decreased by increasing amount of inorganic additives, nearly to fresh granite. Fused silica was more effective than talc in lowering the thermal expansion coefficient. Additionally, lexural and tensile strengths of the composites were getting lower and higher with the amount of the inorganic fillers, respectively. It was thus concluded that an epoxy composite containing inorganic fillers was developed to show much lower thermal expansion coefficient, similar to fresh granite, than the neat epoxy resin, and also proper mechanical strengths for applications.