• Journal of the Korea Safety Management & Science
• /
• v.3 no.3
• /
• pp.11-21
• /
• 2001

Domestic construction industry has considerable level of construction performance and technology thanks to the economic development and as the result of performing diverse oversea construction project. However, construction disasters have been steadily increasing, and do severe disasters at faster pace. Most of such disasters happen at small and small medium-sized construction fields, which contract size is less than 10 billion won. small and medium-sized construction fields are not obliged to designate a safety manager, and have limitations in engaging self-regulating disaster prevention activities due to reduced budget for safety facilities. For the small and medium-sized construction sites with less than 10 billion won, the Ministry of Labor has been carrying out mobile inspections of construction safety. However, the effect so far is insignificant and an improvement plan is required. Therefore, in the present thesis, we derive problems appearing in the current construction safety mobile inspection system, investigate and study systems in foreign countries, and suggest an efficient and effective plan to operate safety technology inspections. First of all, we establish a standard to select sites to be inspected that are high in construction risk and disaster occurrence probability In addition, we suggest a plan to take administrative and judiciary measures based on the total score for disaster factors considering the disaster occurrence probability and the illegal practices. Furthermore, a scheme to maximize the effect of disaster prevention is sought by building an organic cooperative system between the Ministry of Labor, Korea Occupational Safety ＆ Health Agency and other organizations specialized in instruction of construction disaster prevention. Finally, we induce a research conclusion that leads to self-regulating safety management through checking and instructing systematic management on mobile inspections.

• Korean Journal of Construction Engineering and Management
• /
• v.13 no.2
• /
• pp.37-47
• /
• 2012

Engaged number in the construction industry is 45 percentage level against to manufacturing industry. And Induction -factor of Production is much the same to mfg. field, Value added Induction-factor is more higher than manufacturing industry, therefore we research again about workers' inferior working & personal life condition in our society in order to they feel happiness their life with pride for the job construction occupation. So construction companies & government will be contribute to strengthen their phase & to achieve more higher level of construction working culture for elevate competitive power. We have to prepare the basis to turn to the qualitative construction businesses by break away from only the amount of work volume in company with the system of workers' self-conceit on the ground of professional education/training, qualification system, social insurance benefits, working condition improvement, stable job. Our nations does not feel well-being senses, only 25 class level in the 30 countries of OECD. We draw the questions at issue with slough off old customs in order to qualitative improvement for profession & self-contentment of construction workers, and present the useful plan to contribute to international competitiveness with our construction firms in the globalize construction field under Government's & company's policy.

• Journal of the Korean Society of Safety
• /
• v.35 no.2
• /
• pp.76-83
• /
• 2020

This study examined the effects of perceptual differences of safety leadership between managers and workers on workers' safety attitudes and behavior in two construction sites. In addition, the mediating role of safety attitude between safety leadership and safety behavior across discrepancy level of safety leadership. This study was conducted on two first-tier construction companies within the 100th place in 2019. Two companies were similar in size(100 - 150 billion won) and process from the basement frame finishing stage to start of the ground structure of apartment. In A Site, 40 managers and 73 workers, 42 managers and 77 workers in B site participated the survey on managers' safety leadership, and workers' safety attitude and behavior. The results showed that there was no significant difference between the safety leadership scores assessed by the manager and workers at site B. However, the safety leadership scores assessed by the managers were significantly higher than that by the workers at site A. The workers' safety attitudes and behaviors at site B were higher than those of workers at site A. Moreover, Site B was significantly higher in the effects of safety leadership on safety behavior than Site A. At site B, safety leadership had a significant influence on safety behavior even after controlling the safety attitude of workers. At site A, safety leadership had no significant effect on safety behavior after controlling safety attitude. These findings suggest that there is managers' self-serving bias on safety leadership in site A and that this bias of leadership can negatively affect workers' safety attitude and behaviors. In addition, it can be seen that if the self-serving bias on safety leadership occurs, the manager's safety leadership has less influence on workers' safety behavior.

• Advances in concrete construction
• /
• v.10 no.5
• /
• pp.455-462
• /
• 2020

This study investigated the effect of horizontal casting joints on the mechanical properties and structural behavior of sustainable self-compacting reinforced concrete beams (SCRCB). The experimental research consisted of two stages. The first stage used four types of concrete mixtures which were produced to indicate the effects of cement replaced with cement waste at 0%, 5%, 10%, and 15% by weight of cement content on fresh concrete properties of self-compacting concrete (SCC) such as, passing ability, filling ability, and segregation resistance. In addition, mechanical properties such as compressive, tensile, and flexural strength were also studied. The second stage selected the best mixture from the first stage and studied the effect of horizontal casting joints on the structural behavior of sustainable SCRCBs. The effect of horizontal casting joints on the mechanical properties and structural behavior were at the 25%, 50%, 75%, and 100% of sample height. Load deflection, failure mode, and theoretical analysis were studied. Results indicated that the incorporation of replacement with cement waste by 5% to 10% led to economic and environmental advantages, and the results were acceptable for fresh and mechanical properties. The results indicated that delaying the time for casting the second layer and increasing the cement waste in concrete mixtures had a great effect on the mechanical properties of SCC. The ultimate load capacity of horizontal casting joints reinforced concrete beams slightly decreased compared with the control beam. The maximum deflection of casting joint beams with 75% of samples height is similar with the control beam. The experimental results of reinforced concrete beams were substantially acceptable with the theoretical results. The failure modes obtained the best forced casting joint on the structural behavior at 50% height of casting in the beam.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.3
• /
• pp.397-404
• /
• 2021

In this study, it was reviewed that the effect of solid capsules on the quality of surface repair materials and the healing properties of long-term aging, as part of a study to utilize self-healing surface repair materials using solid capsules as repair materials. As a result of evaluation of the rheological properties of self-healing surface repair materials according to the mixing of solid capsules, plastic viscosity, yield stress, and table flow tended to decrease. In the case of compressive strength, 1MPa per 1% of the solid capsule decreased proportionally. As a result of evaluating the long-term healing properties, when 10% of solid capsules were mixed, a healing rate of 90% was shown at 28 days of healing, because the solid capsule was preserved even after 91 days of age had elapsed. after 91 days of healing, even in the case of 5% of solid capsules, a healing rate of 90% was shown.

• Journal of the Society of Disaster Information
• /
• v.16 no.4
• /
• pp.747-757
• /
• 2020

Purpose: This study noted that even similar environmental conditions caused by the heat wave were differentiated depending on the internal characteristics of the individual, so there was a difference in the extent of the damage. Thus, the relationship between individual psychological characteristics and experiences of the symptoms of thermal diseases was analyzed. Method: The influence of construction workers was analyzed through questioning of individual characteristics and psychological measures of self-esteem, self-esteem, and personality that may be related to heat wave damage, depending on whether they have experienced symptoms of thermal diseases. Results: Logistic regression shows that responsibility affects positive (+) experience of symptoms of heat disease and self-esteem in groups negatively (-) experience of symptoms of heat illness. Conclusion: This study presented basic data as the first study to analyze obsessive compulsive, self-respect and personality of construction workers who are vulnerable to heat waves to identify the psychological characteristics of victims of heat waves.

• Advances in concrete construction
• /
• v.9 no.1
• /
• pp.33-41
• /
• 2020

In this study, polyethylene glycol (PEG) and polyacrylamide (PAM) have been used as self-curing agents to produce self-curing concrete (SC). Compressive strength, ultrasonic pulse velocity (UPV), bulk electrical resistivity, chloride ion penetrability, water permeability, and main microstructural characteristics were examined under different curing regimes, and compared to those of the control concrete mixture with no self-curing agents. One batch of a control mixture and one batch of a SC mixture were air-cured in the lab to act as non-water-cured samples. The water curing regimes for the control mixture included continuous water curing for 3, 7, and 28 days and periodical moist curing using wetted burlap for 3 and 7 days. Curing regimes for the SC mixtures included 3 days of water curing and periodical moist curing for 3 and 7 days. SC mixtures showed better microstructure development and durability performance than those of the air-cured control mixture. A short water curing period of 3 days significantly improved the performance of the SC mixtures similar to that of the control mixture that was water cured for 28 days. SC concrete represents a step towards sustainable construction due to its lower water demand needed for curing and hence can preserve the limited water resources in many parts of the world.

• International Journal of Highway Engineering
• /
• v.19 no.1
• /
• pp.11-19
• /
• 2017

PURPOSES : The purpose of this study is to verify the property of self-healing, and to propose an appropriate duration for wet curing of bridge deck concrete overlays. METHODS : In this study, reinforced bars were inserted into concrete molds in order to prevent brittle fracture and induced cracks in the concrete resulting from indirect tension mode. The induced time of concrete cracking was 3 to 7 days, following which the concrete specimens were cured in water. The resulting concrete crack width was measured using image analysis equipment. Additionally, the self-healing tests were performed using the following three mixtures: OPC, SFC, and LMC. RESULTS : Concrete mixtures with crack widths of $150{\mu}m$ or lower were completely healed by Day 28. Hydrates of crack fills were found to be the calcium carbonate. CONCLUSIONS : The cement-based mixtures exhibit properties of self-healing. Considering these properties, it is necessary to increase the curing duration of concrete overlays for bridge decks.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.245-246
• /
• 2022

Recently, research on the self-healing of concrete using bacteria has been actively conducted. The self-healing method using bacteria has a low self-healing rate and the surrounding environment of the fracture site is very important. A previous study to solve this problem involves the manufacture of capsules using 3D printing. Fracture position control was an important topic in 3D printing-based capsules. In this study, to compensate for the shortcomings of existing studies, a capsule capable of selective destruction location control was produced using PDMS-based molds that are not restricted by the environment. Resin capsules were prepared for each part using several molds and a bonding surface was arranged. In order to verify this on the bonding surface, fracture strength and wave unit values were analyzed through a three-way compression experiment. It can be seen that as the curing time increases, the deviation between samples decreases. In addition, through experiments, it was confirmed that the junction surface and wave unit values coincide in all three directions. It can be used for self-healing research using various solutions.

• Korean Journal of Construction Engineering and Management
• /
• v.14 no.1
• /
• pp.115-123
• /
• 2013

Changes have occurred in the professional capabilities of the construction project managers after the global financial crisis. As representatives of construction companies and projects, construction project managers have full responsibility over a construction project. Throughout its life cycle, from design through construction to completion, the business capabilities of such managers are regarded as critical elements in the changes in the country's construction economy. Therefore, this study aimed to determine the main capabilities of current construction project managers, and to analysis of its competitiveness using Important-Performance Analysis(IPA). The results of IPA were as follows; (1)capability to win new contracts and capability to collect information of new project are needed for external relation competitiveness, (2)gerentocratic management mind-set and active breakthrough are needed for internal project management competitiveness, and (3)capability to predict issues and self-improvement are needed for self discipline competitiveness. However, this work is still considered to provide the basic data that can help Korean construction companies who plan to educate the project manager's strengthen their medium and long-term capabilities.