• Journal of the Korean Society of Safety
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• v.34 no.2
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• pp.56-62
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• 2019

Secondary accident is common type of accident which occurs in Korean highway tunnels. Fatality rate of secondary accidents in highway tunnels is six time higher than primary accidents. Video type VMS is a new way of providing information to road users which was recently introduced by Korean government to prevent secondary accidents in highway tunnels. In this study we compared changes in driver's behavior when information is provided by Text type and Video Type VMS. In addition to analyze effects of secondary accident reduction, driving behavior was analyzed based on providing advance information by video type VMS at tunnel entrance. Analysis showed that both text type and video type VMS has similar effect on driver behavior. Video type VMS showed positive effect on driver's behavior to prevent secondary accident when information is provided 1km ahead of accident. Considering there results and the short-term memory characteristics of driver, it was determined that information should be provide at about 650m from the entrance of the tunnel. The results of this study are consistent with the requirement that VMS should be installed at least 500m ahead of tunnel and produce more accurate providing information points. 650m is also appropriate interval for providing information in tunnel to cope with an accident ahead.

• Journal of the Korea Institute of Building Construction
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• v.2 no.3
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• pp.131-138
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• 2002

The objective of the study is to examine the characteristic correlations between reinforcing carbon fiber and interfacial adhesion agent since the interfacial adhesion strength between reinforcing carbon fiber and matrices is believed to be an essential element influencing the physical properties in carbon fiber reinforced cement composite using slurry method. The integrity of interfacial adhesion between reinforcing fiber and cement not only affects the quality of fiber reinforced cement composite but also influences to a large degree the physical properties of the cement composite when producing carbon fiber reinforced cement composite using slurry method. Having analyzed the physical properties 1.e., water content, tensile strength, flexural strength and flexural toughness of carbon fiber reinforced cement composite specimens, C-PAM(cation polyacrylamide) was determined to be an optimum interfacial adhesion agent. The study has also demonstrated that interfacial adhesion strength varies largely on the content and type of the reinforcing fiber. Judging from magnified view of the tensile shear cross-section using VMS(video microscope system), interfacial adhesion strength between reinforcing fiber and matrices is affected by the type of interfacial adhesion agent. According to the result of the experiments, C-PAM was determined to be an ideal interfacial adhesion agent when using carbon fiber in producing carbon fiber reinforced cement composite with the optimum content of carbon fiber being established.