• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.611-618
• /
• 2000

The test facility of the 1/60-scale models for the train-tunnel interactions was recently developed to investigate the effects of entry portal shapes, hood shapes and air-shafts for reducing the micro-pressure waves radiating to the surroundings of the tunnel exits by KRRI in Korea. The launching system of train model was chosen as air-gun type. In present test rig, after train model is launched, the blast wave by the driver did not enter to inside of the tunnel model. The train model is guided on the one-wire system from air-gun driver to the brake parts of test facility end. Some cases of the experiments were compared with numerical simulations to prove the test facility.

• Journal of the Korea Concrete Institute
• /
• v.11 no.4
• /
• pp.117-127
• /
• 1999

In concrete incorporating high volume ground granulated blast-furnace slag that has frozen at early age, to evaluated the results of resistance to freezing and thawing is very difficult because the hydration of the concrete increases over the duration of rapid freezing and thawing test. Hence, the dynamic modulus of elasticity of specimens after freezing and thawing will be favorable results unless the hydration effect is taken into consideration. In this study, a method of evaluating to the resistance to freezing and thawing of concrete subjected freezing at early age, in which the effect of hydration is modified for its increase during rapid freezing and thawing test, is investigated.

• Proceedings of the KSR Conference
• /
• 1999.11a
• /
• pp.146-154
• /
• 1999

The test facility of the 1/60-scale models for the train-tunnel interactions was recently developed to investigate the effects of entry portal shapes, flood shapes and air-shafts for reducing the micro-pressure waves radiating to the surroundings of the tunnel exits by KRRI in Korea. The launching system of train model was chosen as air-gun type. In present test rig, after train model is launched, the blast wave by the driver did not enter to inside of the tunnel model. The train model is guided on the one-wire system from air-gun driver to the brake parts of test facility end. Some cases of the experiments were compared with numerical simulations to prove the test facility.

• Research in Plant Disease
• /
• v.22 no.4
• /
• pp.264-268
• /
• 2016

The nursery test against rice blast in Korea from 2014 to 2015 was analyzed. The average of disease severity of leaf blast in 12 sites showed $3.7{\pm}2.1$ in 2014 and $4.4{\pm}2.1$ in 2015. Disease severity of leaf blast in Icheon and Cheolwon was increased ranging from $2.8{\pm}2.2$ in 2014 to $6.3{\pm}1.8$ in 2015. Using a designation system, a total of 588 isolates collected those years were categorized into 34 races in 2014 and 51 races in 2015 based on the reaction pattern of Korean differential varieties. The blast isolates of 2015 were more diverse than those in 2014. The ratios of KI race to KJ race were 54:46 in 2014 and 70:30 in 2015; however, the predominant race population was KJ-301 as 16%, and KI-101 as 15% in 2014 and 2015, respectively. These results indicate that the distribution of the blast races is getting more diverse in Korea, therefore, this research would provide the possibility to predict race distribution and change to prevent the outbreak of rice blast and will also serve as a useful information for breeding of resistant rice cultivar against blast.

• Korean journal of applied entomology
• /
• v.15 no.4 s.29
• /
• pp.163-168
• /
• 1976

The present study was conducted to determine the number of genes controlling resistance of variety Tongil to three prevalent blast strains and any relationships among the genes in the inheritance of resistance of the variety to blast. Tongil was crossed with five local varieties and the progenies were tested with blast isolates E-7 and 100-14 by injection inoculation method. Results indicated that a tingle dominant gene conditioned resistance of variety Tongil and resistance to the isolate E-7 was controlled by a gene different from that controlling resistance to the isolate 100-14. In previous study it was identified that the gene controlling resistance to the isolate E-7 was different from the gene for resistance to isolate T-1. Therefore based on the foregoing results it may be inferred that the variety Tongil has at least three or more resistant genes to blast.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.5 no.2
• /
• pp.185-191
• /
• 2017

The objective of this paper is to investigate the effect of waste refractory powder(WRP) and desulfurization gypsum(FGD) as activators on the flow properties and the strength development of high volume blast furnace slag mortar incorporating illite(BSM) having adsorption and deodorization. To fabricate the BSMs with 60% of W/B, blast furnace slag are incorporated with 45% and 65%, respectively. WRP and FGD are substituted from 5 to 10%. Test results indicate that the flow is decreased with increase of WRP and FGD, while increase of WRP and FGD enhance the compressive strength due to accelerated reaction of blast furnace slag, The use of illite results in a decrease of compressive strength. pH has increasing tendency until 7days, while it has reduction. In this paper, optimal dosages of WRP and FGD are believed to be around 5% each.

• Resources Recycling
• /
• v.19 no.3
• /
• pp.33-44
• /
• 2010

In this study, the possibility of utilizing carbide lime waste, obtained from the generation of acetylene process, as a alkali activator of blast furnace slag cement was investigated. The physical and chemical analysis of the carbide lime waste was studied and three types lime waste in order to investigate behaviour as alkali activator were used. Lime wastes were added 0, 10, 20 and 30 wt.% in blast furnace slag and blast furnace slag containing lime waste were added 0, 10, 30 and 50 wt.% in OPC. As a result of analysis of hydration properties, in the case of calcium hydroxide rehydrated after heat treatment at $800^{\circ}C$, it was higher hydration rate than other specimens. For the results of compressive strength test, when lime waste passed 325 mesh sieve and rehydrated calcium hydroxide were used, it was higher compressive strength than OPC from hydration 7days. At OPC50 wt.%-BFS45 wt.%-AA5 wt.% system using lime waste of 325 mesh under, the highest compressive strength appeared.

• Journal of the Korean Ceramic Society
• /
• v.39 no.5
• /
• pp.452-459
• /
• 2002

This paper addresses the hydrothermal reactivity of blast furnace slag and fly ash with lime, respectively. The test conditions were CaO-to-$SiO_2$ ratio (C/S), autoclaving temperature ($140{\circ}C$ and $180{\circ}C$) and time (20 to 60h). The study was carried out in terms of the hydrothermal reactivity between $SiO_2$ contained in each hydraulic material and (pure) lime and the compressive strength of autoclaved specimens. Porosity measurement and the XRD analysis were also made in order to ascertain the hydraulicity of the siliceous materials. Compressive strength of the specimens was interpreted in terms of porosity and the reactivity of CaO and $SiO_2$. And the XRD analysis showed the C/S change of the hydrates in the course of autoclaving process. $SiO_2$ in the blast furnace slag was more reactive with CaO than that in the fly ash and consequently the blast furnace slag specimens resulted in much higher compressive strength. A maximum compressive strength of $807kg/cm^2$ was obtained for the blast furnace slag at the autoclaving condition of $180{\circ}C$ and 40 h, while only $397kg/cm^2$ was maximally to achieve with fly ash.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.4
• /
• pp.345-352
• /
• 2011

The purpose of this study was to investigate the expansion of alkali-activated mortar based on ground granulated blast furnace slag containing reactive aggregate due to alkali-silica reaction. In addition, this study was particularly concerned with the behavior of these alkaline materials in the presence of reactive aggregates. The experimental program included expansion measurement of the mortar bar specimens, as well as the determination of the morphology and composition of the alkali-silica reaction products by using scanning electron microscopy(SEM), and energy dispersive x-ray(EDX). The experiment showed that while alkali-activated ground granulated blast furnace slag mortars showed expansion due to the alkali-silica reaction, the expansion was 0.1% at Curing Day 14, showing that it is safe. After the accelerated test, SEM and BEM analysis showed the presence of alkali-silica gel and rim around the aggregate and cement paste. According to the EDX, the reaction products decreased markedly as alkali-activated ground granulated blast furnace slag was used. In addition, for the substitutive materials of mineral admixture, a further study on improving the quality of alkali-activated ground granulated blast furnace slag is needed to assure of the durability properties of concrete.

• Journal of the Korea Concrete Institute
• /
• v.23 no.3
• /
• pp.339-346
• /
• 2011

The effects of mineral admixtures on the bonding properties of cement mortar to polyolefin based synthetic fiber were evaluated. The mineral admixtures consisted of 0%, 5%, 10%, and 15% fly ash, blast furnace slag, and metakaolin in cement. Bond interactions between the cement mortar and the polyolefin based synthetic fiber were determined by Dog-bone bond tests. Bond tests of the polyolefin based synthetic fiber showed an increase in pullout load with the strength of the cement mortar. Also, the interface toughness of polyolefin based synthetic fiber in cement mortar increased as the fly ash, blast furnace slag, and metakaolin contents increased. The microstructure of polyolefin based synthetic fiber surface was examined after the pullout test to analyze the frictional resistant force according to the replacement ratio of fly ash, blast furnace slag, and metakaolin during the pullout process of polyolefin based synthetic fiber in cement mortar. The scratched of polyolefin based synthetic fibers increased with the replacement ratio of fly ash, blast furnace slag, and metakaolin. Also, the interface toughness was enhanced by adhesion forces induced by the fly ash, blast furnace slag, and metakaolin.