• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.11a
• /
• pp.373-374
• /
• 2008

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.42 no.2
• /
• pp.86-92
• /
• 2000

The model using homogenization technique based on energy concept for the prediction of the failure criterion of staple fiber mixed soil was developed to increase the practice and the application of staple fiber as a reinforcement for improving soft ground. Parameters of the model are aspect ratio and volumetric content of fiber, cohesion and internal friction angle of soil, adhesion intercept and interface friction angle of soil and fiber. It is considered that the model developed in this study is applicable to the soil composed of clay, silt and sand mixed by thread types of fiber such as steel bar, steel fiber, natural fiber etc.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.57 no.2
• /
• pp.47-56
• /
• 2015

At the present, the mechanized form roads pavement was constructed with plain concrete. Mostly, it was used by welded wire mesh for preventing crack. Cellulose fibers for the reinforcement of concrete offer relatively high levels of elastic modulus, fiber count (per unit weight), specific surface, and bond strength to cement-based materials. The construction of concrete pavement confirmed that cellulose fiber reinforced concrete was applicable to mechanized form roads pavement. In the study, cellulose fibers were used here at 0.08 % volume fraction, which is equivalent to a fiber content of $1.2kg/m^3$. Cellulose fiber reinforced concrete were compared with plain concrete. Field test results indicated that cellulose fiber reinforced concrete showed slightly to increase of 28 days compressive strength and improved the initial strength. it tended to increase of splitting tensile strength. Test results showed that the slump and air content tend to decreased. but, the variation of air contends is very little. Also, construction cost of cellulose fiber reinforced concrete is less than about 25.7 % the case of welded wire mesh previously used. Therefore, The cost reduction is expected to be possible in construction site by mechanized form roads pavement.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.42 no.4
• /
• pp.360-365
• /
• 2009

The dietary fiber and crude fiber contents of different thallus regions (blade, stipe, and holdfast) in three brown algae (Laminaria japonica, Ecklonia stolonifera, and E. cava) were detennined at different ages, and then compared with one another. On a dry matter basis, the soluble dietary fiber (SDF) content was highest ($10.8{\pm}0.5%$) in the holdfast of 2-year old L. japonica, and the insoluble dietary fiber (IDF), total dietary fiber (TDF), and crude fiber (CF) contents were highest in the holdfast of 2-year old E. cava at $44.5{\pm}0.7%$, $50.2{\pm}0.5%$, $6.8{\pm}0.7%$, respectively. The IDF, TDF, and CF contents of these three species were measured in the following order: holdfast > stipe > blade, and the SDF contents of L. japonica exhibited the reverse of this trend. The TDF/CF ratio of 1-year old L. japonica, E. stolonifera, and E. cava was greater than was observed in the corresponding 2-year old samples. This is, to the best of our knowledge, the first report demonstrating that the holdfasts of L. japonica, E. stolonifera, and E. cava are rich in dietary fiber contents, especially IDF, TDF, and CF.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.27 no.2
• /
• pp.47-56
• /
• 1985

Wasting fiberous residues from the cutting processes of steel materials at an iron-Works were mixed with concrete. The strength and toughness of steel fiber concrete with different steel contents were tested in a laboratory. The test results showed that the steel fiber residues can be used for the reinforcement of concrete. The potential applications of such product include floor constructions for facilities like dairy barns, grain storages, and machinery shops. The test results are as follows. 1. The compressive strengths of steel fiber concrete with one percent steel content by volume were 20 percent greater than that of plain concrete. The treatments also increased the concrete toughness by 96 percent. 2. When applied to tensile forces, the steel fiber concrete showed the increased strengths by 20 percent, and the toughness by 48 percent. 3. The steel content levels greater than or equal to 1.5 percent by volume resulted in the decreases of the compressive and tensile strengths of steel fiber concrete by 10 percent as compared to plain concrete. The concrete toughness increased with the steel contents. 4. The reinforcement effects of steel fiber depend on the quality of fiber material being used. Good steel fiber for concrete reinforcement appears to be uniform in shape and component, fine and long, and round-shaped.

• Advances in concrete construction
• /
• v.10 no.3
• /
• pp.257-269
• /
• 2020

The aim of this study is to investigate the flexural performance of hybrid fiber reinforced self-compacting concrete (HFRSCC) having different ratio of micro and macro steel fiber. A total of five mixtures are prepared. In all mixtures, the sum of the steel fiber content is 1% and also water/binder ratio is kept constant. The amount of high range water reducer admixture (HRWRA) is arranged to satisfy the workability criteria of self-compacting concrete. Four-point bending test is carried out to analyze the flexural performance of the mixtures at 28 and 56 curing days. From the obtained load-deflection curves, the load carrying capacity, deflection and toughness values are investigated according to ASTM C1609, ASTM C1018 and JSCE standards. The mixtures containing higher ratio of macro steel fiber exhibit numerous micro-cracks and, thus, deflection-hardening response is observed. The mixture containing 1% micro steel fiber shows worst performance in the view of all flexural parameters. An improvement is observed in the aspect of toughness and load carrying capacity as the macro steel fiber content increases. The test results based on the standards are also compared taking account of abovementioned standards.

• Korean Journal of Food Science and Technology
• /
• v.28 no.4
• /
• pp.702-706
• /
• 1996

Husked barley contained 17.2% dietary fiber and naked barley contained 14.9% dietary fiber. The barley was ground in a Udy cyclotec mill having a 0.5 mm screen and sieved with a 400-mesh screen (38 m openings). Coarse material of naked barley retained by the screen, with a weight yield of 54.1%, contained 7.0% soluble dietary fiber, 13.9% insoluble dietary filer and 20.9% total dietray fiber. As the naked barley flour level increased in bread baking, the water absorption, mixing time, and loaf weight increased, but the loaf volume decreased. Barley flour was added to wheat flour at a replacement level of 10% without a large adverse effect on bread quality, and the dietary fiber content of bread was increased from 3.0% to 5.0%. The soluble dietary fiber content was not changed, but the insoluble dietary fiber content was increased during the baking process.

• Computers and Concrete
• /
• v.27 no.5
• /
• pp.417-435
• /
• 2021

The optimal distribution of steel fibers over different layers of concrete can be considered as an appropriate method in improving the structural performance and reducing the cost of fiber-reinforced concrete members. In addition, the use of waste tire rubber in concrete mixes, as one of the practical ways to address environmental problems, is highly significant. Thus, this study aimed to evaluate the flexural behavior of functionally graded steel fiber-reinforced concrete containing recycled tire crumb rubber, as a volume replacement of sand, after exposure to elevated temperatures. Little information is available in the literature regarding this subject. To achieve this goal, a set of 54 one-, two-, and three-layer concrete beam specimens with different fiber volume fractions (0, 0.25, 0.5, 1, and 1.25%), but the same overall fiber content, and different volume percentages of the waste tire rubber (0, 5, and 10%) were exposed to different temperatures (23, 300, and 600℃). Afterward, the parameters affecting the post-heating flexural performance of concrete, including flexural strength and stiffness, toughness, fracture energy, and load-deflection diagrams, along with the compressive strength and weight loss of concrete specimens, were evaluated. The results indicated that the flexural strength and stiffness of the three-layer concrete beams respectively increased by 10 and 7%, compared to the one-layer beam specimens with the same fiber content. However, the flexural performance of the two-layer beams was reduced relative to those with one layer and equal fiber content. Besides, the flexural strength, toughness, fracture energy, and stiffness were reduced by approximately 10% when a 10% of natural sand was replaced with tire rubber in the three-layer specimens compared to the corresponding beams without crumb rubber. Although the flexural properties of concrete specimens increased with increasing the temperature up to 300℃, these properties degraded significantly with elevating the temperature up to 600℃, leading to a sharp increase in the deflection at peak load.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.481-482
• /
• 2009

This study analyzed fire resistance characteristics of high strength concrete according to changes in curing method and PP fiber content, and the results are as follows. First in case of standard curing, spalling was prevented at PP fiber content of 0.05 % or higher. Autoclave and steam curing showed prevention of spalling at content of 0.1 % or higher. For residual compressive strength, measurement of strength for plain was impossible due to spalling phenomenon. A satisfactory trend was shown with increase in PP fiber content with the strength of about 30 MPa.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.2 s.130
• /
• pp.40-55
• /
• 2005

This study was carried out to discuss the feasibility of wood and plastic wastes as the raw materials for wood particle-plastic composites. For this purpose, composites were manufactured from coarse and fine wood particles and polypropylene fibers by nonwoven web process. And the effect of wood particle size on the performance of the composites were analyzed according to ASTM D 1037-93. In the physical properties of composites, water absorption decreased with the increase of target density and polypropylene fiber content. And the composites with fine wood particles appeared to have slightly lower water absorption than those with coarse wood particles. Thickness swelling did not vary significantly with the increase of target density but increased with the increase of wood particle content. And the composites with fine wood particles were significantly lower in thickness swelling than those with coarse wood particles. In the mechanical properties of composites, dry and wet MOR showed the increasing tendency with the increase of polypropylene fiber content and target density. Dry and wet MOE showed the increasing tendency with the increase of target density but only wet MOE exhibited the increasing tendency with the increase of polypropylene fiber content. Composites with fine wood particles appeared to be generally higher in wet MOR and MOE than those with coarse wood particles. In conclusion, composites with fine wood particles showed generally higher performance than those with coarse ones. Also, composites were significantly superior to control particleboards in the performance, especially in water absorption and thickness swelling.