• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.10-19
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• 2013

Recently, researches related to precast modular construction have been actively conducted for nuclear power plant, LNG gas tank, and small-medium PCCV as well as bridges and buildings. In this study, the precast panel cast with steel mesh reinforced mortar (SRM) which is similar reinforced ferrocement was developed for efficient precast construction, construction time reduction, and easy transportation. Mortar mixture with high strength and flowability was obtained from various case studies using silica fume and GGBS. Also, $1,200{\times}600{\times}150mm$ SRM and reinforced concrete (RC) panels were manufactured with reinforcing ratio of 2% and 4%. To verify structural performance of the SRM specimen, the basic material tests, free shrinkage test, and 3-point flexural test with a line loading were carried out. From the test results, it was determined that SRM specimens showed outstanding flexural capacity and ductility. However, the 4% reinforced SRM specimens must consider shear reinforcing to be used as a precast modular member.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.3
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• pp.125-131
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• 2013

In order to protect agricultural products against damage by physical load, various shock absorbing materials is used. As the demands of environment protection increase, the use of plastic materials have been restricted. On the other hand, Pulp mold products have some benefits - easy manufacturing, superior shock absorbing and eco-friendly. In order to develop pulp mold tray for melon packaging as shock absorbing packaging material, we investigated physical properties and vibration transmission characters of 180, 200 and 220 g pulp mold tray for melon. As the weight of pulp increased, compression strength and shock absorbing performance increased, while vibration transmissibility decreased. Especially in case of 180g pulp mold tray, it is not suitable for melon packaging because the transmitted vibration acceleration was higher than the forced vibration acceleration. And 200g pulp mold tray is suitable for melon packaging because the vibration transmissibility was lowest in three trays. And the vibration acceleration transmitted to the melon in edge of pulp mold tray was higher than to the melon in center of pulp mold tray. As the result of the simulated transportation test, the firmness of melon packaging using pulp mold tray was higher than that of conventional packaging. Therefore, these results suggest that pulp mold tray packaging could be suitable for melon packaging.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.2
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• pp.114-119
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• 2013

The present study tested 5 concrete mixes to develop reliable mixing proportions for the sustainable alkali-activated(AA) foamed concrete as a thermal insulation material for the floor heating system of buildings. The AA binder used was composed of 73.5% ground granulated blast-furnace slag, 15% fly ash, 5% calcium hydroxide, and 6.5% sodium silicate. As a main variable, the unit binder content varied from $325kg/m^3$ to $425kg/m^3$ at a space of $25kg/m^3$. The test results revealed that AA foamed concrete has considerable potential for practical applications when the unit binder content is close to $375kg/m^3$, which achieves the minimum quality requirements specified in KS F 4039 and ensures economic efficiency. In addition, lifecycle assessment demonstrated the reduction in the environmental impact profiles of all specimens relative to typical ordinary portland cement foamed concrete as follows: 99% for photochemical oxidation potential, 87~89% for global warming potential, 78~82% for abiotic depletion, and 70~75% for both acidification potential and human toxicity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1422-1429
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• 2009

Alaska pollock roe is mainly used as a raw material for fermented seafood, especially in the East Asia. Kernels of Alaska pollock roe are not valuable as a raw material and usually discarded as a waste product. In order to utilize the broken roes of Alaska pollock, the smoked product, a imitated sausage, was manufactured for commercial production. Texture intensity (hardness and gumminess) and sensory evaluation (taste and acceptability) of the smoked Alaska pollock roe packed with collagen casing were evaluated based on mixture design and regression models. At higher concentration of carrageenan and lower concentration of starch in the formula of the smoked Alaska pollock roe, higher texture intensity and sensory scores were obtained. pH values of all treatments (control, vacuum and $N_2$ packages) increased up to 6.28, 6.23 and 6.24 on 4 months of storage, respectively, and then decreased. The numbers of VBN, TBA and viable cell counts increased during storage periods, higher in control than in vacuum and $N_2$ packages. Coliform bacteria was not detected in all treatment during storage periods.

• Resources Recycling
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• v.20 no.1
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• pp.37-45
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• 2011

This study was conducted to recycle flotation tailings as non-sintered construction materials considering the economic and eco-friendly treatments. The particle size distribution( median $220\;{\mu}m$) of flotation tailings from Soon-shin mine was confirmed to be larger than that(median $140\;{\mu}m$) of tailings from Sam-kwang mine. Thus we investigated the properties of non-sintered eco-brick producted with the tailings from Sam-kwang mine and non-sintered water permeable block producted with the tailings from Soon-shin mine. Compressive strength of non-sintered water permeable block which was made with less than 25 wt% of tailings from Soon-shin mine was met with products class(over 14.70 MPa) of water permeable concrete(EL 245) from KEITL. Meanwhile, the coefficient of its permeability wasn't met with the products class( over $1.0{\times}10^{-2}\;cm/sec$). The properties of non-sintered eco-brick with less than 40 wt% of tailings from Sam-kwang mine were satisfied with third class in sintered clay brick products standard(KS L 4201). The non-sintered eco-brick as a result of leaching test on heavy metals by KSLT was verified to be environmentally stabile.

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.197-204
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• 2016

Concrete walls of neutron generating facilities such as fusion reactors and fission reactors become radioactive by neutron irradiation. Both low-activation and neutron shielding are a critical concern at the dismantling stage after the shutdown of facilities with a requirement of radioactive waste management. To tackle this, two types of additives were investigated in fabricating mortar specimens: synthetic high polymers and boron carbide. It is well known that a hydrogen atom is effective in neutron shielding by an elastic scattering because its mass is almost the same as that of the neutron. And boron is an effective neutron absorber with a big neutron absorption cross section. In this study, the effect of the type, shape, and size of polymers were investigated as well as that of boron carbide. Total 16 mix designs were prepared to reveal the effect of polymers on mechanical properties and neutron shielding performance. The neutron does equivalent of polymers-based mortar for fast neutrons decreased by 36 %, and the count rate of boron carbide-based mortar with regard to thermal neutrons decreased by 90 % compared to conventional mortar. These results showed that a combination of polymers and boron carbide compounds has potential to reduce the thickness of neutron shields as well as radioactive waste from reactors.

• Journal of the Korea Concrete Institute
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• v.27 no.3
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• pp.237-244
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• 2015

Entering the 20th century since the industrial revolution, the cement has been widely used in the field of construction and civil engineering due to the remarkable development of construction industry. However, result from that development, each kind of industrial by-products and waste and the carbon dioxide generated in the process of cement production cause air pollution and environmental damage so earth is getting sick now slowly. Therefore, we have to recognize importance about this. It means that the time taking specific and long-term measures have come. In this research paper, as substitution of the cement generating environmental pollution, we investigate the hydration reaction of non-Sintered Cement mortar mixed with GBFS, active stimulant of alkaline and sulphate series by using SEM and XRD, mechanical and chemical properties according to the curing method. As a result of this experiment, NSC realized outstanding strength for water curing and steam curing. It means that it has a good possibility as substitution of cement. From now on, it can be used for structure satisfying specific standard. We expect to find a substitution of outstanding cement by progressing continuous research making the best use of pros and cons according to the curing method.

• Resources Recycling
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• v.17 no.4
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• pp.3-9
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• 2008

The total amount of fluidized bed incinerator ash, i.e. incombustion materials generated from the municipal solid waste incineration(MSWI) in Korea was approximately 14,000 tons in 2006. Most of the ash after ferrous metal separation is finally discard to the landfill sites. In the present work, possibility for recycling of the ash is studied to utilize the ash as raw materials for ceramic products. Incombustion materials obtained from the two different incinerators were used to recover the raw materials by applying the magnetic separation and screening process to remove metallic particles. The raw materials show relatively low heavy metals content obtained from the KSLP leaching tests. The ceramic products were prepared by mixing the clay with the various amounts of the raw material. The physical properties, i.e. shrinkage rate, absorbancy and compressive strength of the ceramic products sintered at $1,000^{\circ}C$ and $1,050^{\circ}C$, respectively were improved by increasing the addition amounts of the incinerator ash. Based on the leaching tests the ceramic products also be satisfied with the standard limits on the leachability of heavy metals because most of the metallic materials are effectively removed from the incombustion materials by appling the separation processes.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.473-477
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• 2013

The aim of this study was to identify the optimal ingredient-mixing ratio of Job's-tear and wheat flour subjected to extrusion. A modified distance-based mixture design analysis was chosen for the experimental design. The results showed that the bending failure force, the a-value, and the water absorbtion index (WAI) value had no correlation with the mixture ratio of Job's-tear and wheat flour. However, the diameter of the extrudates, the L- and b-values, and the water solubility index (WSI) value were all found to be correlated to the mixture ratio. While the first three values were determined using a linear model, the WSI value was determined using a quadratic model. The diameter and color had an inverse correlation to the mixture ratio: the higher the ratio of Job's-tear to wheat flour, the lower the diameter and darker the color. The L- and b-values were found to change in accordance with the mixture ratio of Job's-tear to wheat flour. The lowest WSI value was obtained at a 40:60 ratio of Job's-tear to wheat.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5636-5645
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• 2015

Physical characteristics of aggregates affect the workability and strength of mortar and concrete, which include their fineness ratio, particle size distribution and water absorption. The workability of construction materials decreases if the incorporated fine aggregates show improper size distribution of their particles. This study shows the particle size effect on the rheological behavior of mortar and provides basic information for evaluating its workability. A mini-slump flow test was adopted to evaluate the workability of mortar. In addition, its plastic viscosity and yield stress were measured using a rheometer for building materials. The sand samples were prepared by sieving river sand and sorting out with their particle sizes. As a result, it was observed that the fines less than 0.7 mm increases the yield stress and plastic viscosity of the mortar samples. If the fines are less than 0.34 mm, the water absorption of the fines dominates change on the workability.