• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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• pp.179-186
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• 2014

Weathering indexes of the typical pedons derived from different parent materials of the soils of Korea were calculated by Kronberg and Nesbitt (1981) to understand weathering degree of the soils which might give a clue of soil formation and characterizing a soil pedon. The weathering index W1 was chemical change index, and the weathering index W2 was silicate dominant index. The chemical compositions of the 49 typic pedons were extracted from the Taxonomical Classification of Korean Soils (NIAST, 1999). The weathering indexes of Kimhae series, derived from fluvio marine material, were the highest among the analyzed soils. Within parent materials, the weathering indexes of the soils derived from limestones parent materials were high, and those derived from phorphyry materials were low. The relationship between W1 and W2 showed unique pattern which implied certain sequence within the same parent materials.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.882-889
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• 2004

Wetness index obtained from topography data of Woogak Mountain was compared with chemical alteration index(CAI), clay minerall contents of rock, and magnetic susceptibility changes of outcrops, and they show a close interrelationship. It is shown that the wetness index can be used as a quantitative indicator of the weathering degree of rocks. Moreover, wetness index simulate quantitatively the hydrologic condition of the local area. Therefore, it is anticipated that wetness index can be used as the data that calculate the weathering speed of rock and weathering grade in the study of weathering sensitivity of rock.

• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.147-157
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• 2003

The application in steel structures is increasing the mill sheet for the weathering steels by minimum maintenance cost in a life cycle cost. These have been collected and statistically analyzed to investigate chemical compositions, mechanical properties, weldability indices, weathering index and impact absorbed energy. From this study, although the band of dispersion in chernical compositions, mechanical properties and impact absorbed energy of the weathering steels appeared a little larger, the results revealed that these values have adequately satisfied the standard values of the Korean Standard. Furthermore, it was found that the weldability indices and the weathering index for the weathering steels have respectively satisfied the value prescribed by the Japanese Highway Specification and ASTM.

• The Journal of Engineering Geology
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• v.27 no.1
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• pp.67-79
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• 2017

Evaluation of the weathering index using the quantitative element composition of rocks is very effective in predicting the degree of weathering of rocks and the secondary weathering residuals. While the process of weathering varies according to the types of rocks, the study of weathering in Korea is concentrated on acidic igneous rocks. This study calculated the weathering indices using whole rock analysis (X-ray fluorescence analysis) of sandstone, mudstone, and shale belonging to clastic sedimentary rocks. The statistical significance of the indices was examined based on the correlation of the calculated weathering indices. Clastic sedimentary rocks showed higher significance of Wp, CIA, CIW and PIA weathering index indicating weathering of feldspar. Chemical Index of alteration (CIA) has the advantage of predicting weathering pathway and clay mineral production, but it is effective to consider chemical index of weathering index (CIW) simultaneously to improve accuracy. In order to reduce uncertainties due to carbonate rocks and to estimate the accurate weathering index, rock samples with high CaO content should be excluded from the evaluation of weathering index.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.383-389
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• 2022

Natural(outdoor) and accelerated(artificial) weathering tests were performed to investigate their influence on polycarbonate. The polycarbonate materials were prepared of various formulations divided into three batches, with existing, development materials1, development materials2, containing mixture of UV additives. Weathering tests were carried out as outdoor weathering(Seosan, South Korea) and accelerated weathering(xenon-arc), and the results analysis were evaluated based on yellow-index(YI), scanning electron microscope(SEM/EDS), energy dispersive x-ray spectroscopy(XRD), and gel permeation chromatography(GPC). Among the three materials, processing method development materials1 with UV stabilizer was excellent in weathering. This study can provide basic data for standardization of development and performance evaluation on livestock barn roof.

• Journal of the Korean Geographical Society
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• v.28 no.2
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• pp.99-111
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• 1993

The transformation of rocks into unconsoli-dated debris is the prime geomorphic processes including weathering and soil forming process. In these processes, rocks tend to be unconsol-idated debris with small particles. Particularly, typical granite is more likely affected by weathering, since the rock consists of quartz, feldspar and mica that can be easily coarse-grained and well jointed without bedding. The purposes of this study are to clarify the index and properties of mechanical weathering that contributed to transformation of granite distributed in Korea. A total of seventy-three samples of weathering products of granite in Korea were collected during the three-year period, March 30, 1989 to February 21, 1992. The prticle analysis was performed for clay, silt and sand using Sieve and Hydrometer. The results of the analysis are as the followings: First, soil textures in the study area are included seven categories of textures as C, CL, SCL, Sil, SL, LS, and S. Among these textures, the most frequent soil texture were SL, S and SCL in order. Second, the weathering products of granite are crumbled by weathering and hydrothermal. Clay texture consisted of fine materials seems to be influenced by hydrothermal, while Sand texture composed of coarse materials, seems to be significantly influenced by weathering. Third, the index of mechanical weathering by region indicates that Hawngdeung(1) is the lowest as 2.37 and the index by soil texture shows that Clay texture is the lowest as 2.46. Forth, the regression analysis of MW showes that sand/clay variable is the most significant variable. Finally, pedochemical weathering is prevailed on the clayey gruss and geochemical weathering is on the gruss and shattering is on the weathered rock, strongly, but the fine materials in some sites were formed by argillation of hydrothermal.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.127-135
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• 2012

The processes of chemical and physical weathering occur simultaneously. The objective of this study was to estimate the degree weathered using fractal dimension through comparison with chemical characteristic of soil samples from Pohang (PH) and Kimpo (KP). Comparing chemical characteristics with fractal dimension, $SiO_2$, $Na_2O$, $K_2O$ content decreased and loss of ignition increased as fractal dimension increased. And fractal dimension showed high correlation with CWI while ATI, STI CIW, PI, CIA and RR demonstrated different degrees of correlation with fractal dimension. The tendency of the changes in oxide content and chemical weathering index with increasing fractal dimension appeared to be similar with the chemical changes due to weathering. Therefore, fractal dimension could be a good indicator representing the extent of weathering and chemical changes.

• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.127-140
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• 1999

In this study, decomposed granite soil samples were taken from 16 different regions and their weathering properties were investigated by testing their physical and chemical properties. According to the results, the Chemical Weathering Index (CWI) ranges from 15.5 to 30 in general and 12 out of the 16 regions show over 20 in CWI. The 12 regions are categorized into complete granite soil areas by Sueoka's classification. CWI, Li. $SiO_2,\; \DeltaS/S$ and SAR are all correlated significantly and used as indicators by which the degree of weathering can be judged. The degree of weathering can be measured especially through Li or $SiO_2$ which is considered as an easy approach of geotechnical classification. Also, the relationship between the value of N and Li is regarded as a good indicator in estimating the degree of weathering.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.717-721
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• 2010

Soil volume conversion factors are used for estimation of an excavated the soil volume which will be removed or added in levelling the ground surface of a construction site. An accurate evaluation method will help us reduce a construction cost and time consuming. In this study, we performed the laboratory tests, including grain size measurement, water content, specific gravity, porosity, density and XRD tests, to suggest reliable soil volume conversion factors and weathering indices in field using nondestructive methods. The weathering index and soil volume conversion factor L are obtained for different types of soils. At results, the CIW index is the best method measuring the weathering index and the factor L is relative to natural porosity, void ratio, density and dry density.

• Corrosion Science and Technology
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• v.6 no.3
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• pp.128-132
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• 2007

For a quantitative inspection on the performance of weathering steel bridges, we have investigated the relationship between the corrosion rate and the composition of the rust layers formed on weathering steel bridges located in various environments in Japan and applied a protective ability index (PAI) to the bridges. The corrosion rates were clearly classified by the PAI, ${\alpha}/{\gamma}*$ and sub index of $({\beta}+s)/{\gamma}*$, where $\alpha$, \gamma*, $\beta$ and s are the mass ratio of crystalline $\alpha-FeOOH$, the total of $\gamma$-FeOOH+ $\beta$-FeOOH + the spinel-type iron oxide (mainly $Fe_3O_4$), $\beta-FeOOH$ and spinel-type iron oxide, analyzed by powder X-ray diffraction, respectively. In the case of ${\alpha}/{\gamma}$*>1, the rust layer works protective enough to reduce the corrosion rate less than 0.01 mm/y. The sub index $({\beta}+s)/{\gamma}*$<0.5 or >0.5 classifies the corrosion rate of the non-protective rust layers, therefore the former state of the rust layer terms inactive and the latter terms active. The quantitative inspection of a weathering steel bridge requires a performance-inspection (PI) and periodical deteriorationinspections (DI). The PI can be completed by checking of the PAI, ${\alpha}/{\gamma}*$. The DI on the weathering steel bridges where deicing salt is sprinkled can be performed by checking the PAI, $({\beta}+s)/{\gamma}*$.