• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1298-1303
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• 2009

The effect of blending weight and fiber length on the tensile and flexural strength for Basalt fiber reinforce cement composites is discussed. The increase of physical properties is mainly affected by blending quantity of fibers instead of the fiber length. Also it is believed that the interfacial adhesion between Basalt fiber and cement matrix gives positive influence to the physical strength. Basalt fiber in saturated $Ca(OH)_2$ solution, which is similar to the alkaline hydration environment of cement, shows very low weight loss even after 3 weeks of immersion.

• Resources Recycling
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• v.24 no.6
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• pp.61-68
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• 2015

In this study, the strength properties of NHL based mortar with blending basalt fiber were investigated. In the first step, it was evaluated that physical properties of NHL based mortar according to mixing method of four types of basalt fiber and then mixing method of one type was selected. As a result of assessment, it showed that the physical properties with mixing method of dry blending were better than that of wet blending and mixing method that basalt fiber pre-mixed with NHL for 5 min in a blender was selected and water and aggregate were finally added. Secondly, the investigation of blending fiber length on the compressive and flexural strength for basalt fiber reinforced NHL based mortars was carried out. The compressive strength was decreased with adding fiber, and the flexural strength was increased more than plain mortar. In the case of adding 6 mm fiber, the compressive and flexural strength were improved more than that of others.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.63-67
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• 2016

Mineral hydrate is a new insulation material that compensates for the defects of existing materials. Mineral hydrate is made of inorganic ingredients; therefore, it is nonflammable. The porous structure of mineral hydrate makes the material lightweight and insulating. Mineral hydrate insulation and similar products have been studied and manufactured in Korea and abroad. However, these insulation materials need to improve in terms of strength. In this study, basalt fiber was used to enhance the strength. In order to observe the property changes, compressive strength, heat conductivity, and specific gravity were measured and XRD pattern analysis was performed. These tests confirmed that basalt fiber was effective at improving the strength and lowering the heat conductivity of mineral hydrate insulation.

• International Journal of Ocean System Engineering
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• v.1 no.3
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• pp.148-154
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• 2011

Generally, strength degradation is caused by the absorption of moisture in composites. For this reason, a fracture is generated in the composites and traces of glass fiber degrade human health and physical damage is generated. Therefore, in this research, we studied the mechanical properties change of composites by moistureabsorption. The composites were manufactured with and without the Gel-coating process and were immersed in a moisture absorption device at $80^{\circ}C$ for more than 100 days. The mechanical properties of the moistureabsorption composites and the composites which dry after moisture-absorption were compared. The mechanical properties degradation of basalt fiber composites according to the result of the measurement of moistureabsorption was smaller than that of glass fiber composites by about 20%. In addition, the coefficient of moisture absorption was lower for the case of Gel-coating processing than the composites without the Gel-coating process by about 2% and it was deduced that Gel-coating did not have a significant effect on the mechanical properties.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.74-82
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• 2003

In this paper, an experimental program was undertaken to test the analysis on Component and mechanical characteristics for crushed stone of excavated Rocks from Sandstone, Shale, Mudstone, for use as a new source of aggregate. Physical and mechanical properties, required for aggregate materials, of major constituents of rock wastes including Sandstone, Shale, Mudstone, Felsite, Basalt, Marl were measured in the laboratory Test results showed that the Shale, Felsite, Basalt tested in this study might possibly be used for construction aggregates. In case of Sandstone and Mudstone, some physical properties such as rock strength were generally adoptable but the aggregate characteristics were lower than required.

• Economic and Environmental Geology
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• v.32 no.1
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• pp.1-11
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• 1999

In the last decade, the supply of natural aggregates has been continuously increased due to the other types of aggregates. In general, aggregates constitute 70-80% of the total volume of concrete, so the quality of aggregates is main factor controlling physical characteristics of concrete. For this reason, physical properties of aggregate according to different rock types were studied. The majority of crushed aggregates is taken out of granite, gneiss, sandstone, andesite, basalt and so forth. The physical properties of these rock types were tested and most of them fell within the acceptable limit on the base of Korean standard regulation. The major lithology of the crushed aggregates is granite and gneiss, both of which are marked for more than 50% of total lithology thpes in Korea. A to the physical properties of granite, the high specific gravity coincides with low porosity, low absorption ratio, while the abrasion and soundness index show, in general, no specific trend. It has been assumed that slight differences of the physical properties of granite aggregates are related with those of the mineral composition, grain size, and so on. In comparison to granite, the physical properties of gneiss have little correlation one after another. This trend is related to different mineral composition, grain size and typical sheet fractures typically prevailing in the texture of gneiss. Spatial pattern of physical properties shows that high specific gravity of granite coincides only with low porosity and absorption ratio in all provinces except Cheolla province, and high specific gravity of gneiss coincides with low porosity and absorption ratio only in Cheolla and Gandwon provinces.

• Elastomers and Composites
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• v.54 no.2
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• pp.91-96
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• 2019

The purpose of this study was to examine the effect of different yarn twisting methods on physical properties. Plain single jersey structured fabrics were knitted from Kevlar yarn, and from Kevlar/HPPE, and from Kevlar/Basalt fiber, and from Kevlar/Glass fiber and Kevlar/Stainless steel fiber blended and core-spun yarns. and then, The fabrics were coated NBR Latex. The physical properties, including tear strength, modulus, degree of penetration, heat resistance, and cut resistance of the knitted fabrics were investigated and compared. Kevlar/HPPE blended yarn fabrics recorded the highest heat resistance (13 Sec.). and Kevlar/HPPE blended yarn fabrics had good cut resistance (Cut Level 4).

• Journal of the Korean Geotechnical Society
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• v.31 no.7
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• pp.41-52
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• 2015

Volcanic rocks in Jeju Island have vesicular structure caused by various environmental factors, and indicate the differences in geological and mechanical characteristics from region to region. In addition, the bedrock of Jeju Island shows stratified structure, that is, soft layers composed of pyroclastic rocks or cavities are irregularly developed between the basalt layers by several times of volcanic activity. In this study, various physical tests and unconfined compressive strength test were conducted for intact rocks sampled in northwestern onshore and offshore of Jeju Island. The results obtained in the tests were compared with the physical and mechanical characteristics of intact rocks sampled in southeastern offshore of Jeju Island. As a results, it was confirmed that the physical and mechanical characteristics of basalts sampled in northwestern Jeju Island were similar to those of basalts sampled in southeastern offshore of Jeju Island. In addition, it was possible to estimate approximate design parameters from the correlation of mechanical properties with physical properties of basalts in Jeju Island.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.205-217
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• 2024

This study evaluated the physical characteristics and quality of volcanic rocks distributed in the Jeju Island-Ulleung Island area as aggregate resources. The main rocks in the Jeju Island area include conglomerate, volcanic rock, and volcanic rock. Conglomerate is composed of yellow-red or gray heterogeneous sedimentary rock, conglomerate, and encapsulated conglomerate in a state between lavas. Volcanic rocks are classified according to their chemical composition into basalt, trachybasalt, basaltic trachytic andesite, trachytic andesite, and trachyte. By stratigraphy, from bottom to top, Seogwipo Formation, trachyte andesite, trachybasalt (I), basalt (I), trachybasalt (II), basalt (II), trachybasalt (III, IV), trachyte, trachybasalt (V, VI), basalt (III), and trachybasalt (VII, VIII). The bedrock of the Ulleung Island is composed of basalt, trachyte, trachytic basalt, and trachytic andesite, and some phonolite and tuffaceous clastic volcanic sedimentary rock. Aggregate quality evaluation factors of these rocks included soundness, resistance to abrasion, absorption rate, absolute dry density and alkali aggregate reactivity. Most volcanic rock quality results in the study area were found to satisfy aggregate quality standards, and differences in physical properties and quality were observed depending on the area. Resistance to abrasion and absolute dry density have similar distribution ranges, but Ulleung Island showed better soundness and Jeju Island showed better absorption rate. Overall, Jeju Island showed better quality as aggregate. In addition, the alkaline aggregate reactivity test results showed that harmless aggregates existed in both area, but Ulleungdo volcanic rock was found to be more advantageous than Jeju Island volcanic rock. Aggregate quality testing is typically performed simply for each gravel, but even similar rocks can vary depending on their geological origin and mineral composition. Therefore, when evaluating and analyzing aggregate resources, it will be possible to use them more efficiently if the petrological-mineralological research is performed together.

• Journal of the Korean Geotechnical Society
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• v.36 no.7
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• pp.29-40
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• 2020

In this study, various laboratory tests were conducted to evaluate the effect of the moisture conditions of Jeju basalt on the mechanical properties. Twenty specimens were produced respectively from basalts collected from Sangga-ri and Eoeum-ri in northwestern Jeju. The tests were performed under saturated and dry conditions, and the results of these tests were used to examine the relationship with the physical properties and the mechanical properties depending on the moisture conditions. As a result of analysis with the test results and references, it was found that the uniaxial compressive strength, Brazilian tensile strength and elastic modulus in the saturated condition decrease at a similar ratio as compared with the dry condition. Also, the Brazilian tensile strength and the uniaxial compressive strength were in a linear proportional relationship, and in the moisture conditions, this relationship was not significantly affected.