In this study, a series of studies is intended to elicit the improvement of the quality of Admixture Substitute Concrete using oil refined for petrochemical work (ERCO). In other words, ERCO is used to analyze the basic properties of Admixture Substitute Concrete by pre-adding the AE liquid solution on its products. As an experimental variable, the method of adding ERCO was added after mixing it with concrete. In addition, the mixing ratio was planned to be 2 levels of 0, 0.5 %, and the total volume of the AEs injection quantity is 5 % that combines 0, 1, 2, and 3 % of the mixed ERCO mass of concrete. As a result, as the pre-injection of AE was increased, the characteristics of the concrete showed that the slump, and air contents were not improved, and the pre-adopting effects of AE agent were also significantly increased in the concrete.

In this study, concrete slab with insulation and non-insulated formwork was used to monitor and control its strength using a wireless sensor network with equivalent age method. As a result, the temperature and compressive strength of the structures were monitored without any problems, which revealed a good management tool.

In this study, the purpose of the study is to determine the depth of damage caused by early frost damage in concrete slab structures under the conditions of external temperature during winter. In other words, we intend to analyze the depth variation of the early frost damage as the thickness of the concrete slab member changes under the condition of the 3-component binder frequently used in practice. As a result, the thinner the component, the significantly reduced the overall temperature of the concrete. In addition, the thinner the component thickness, the higher the delay in increasing the brightness of the core collected from the concrete member, and the greater the effect on the depth of the early frost damage was on the thinner the component thickness.

The objective of this paper is to provide the feasibility of premixed type ternary blended aggregates using raw fly ash(Ra), crushed sand(CS) and sea sand(SS) by studying fresh properties of the concrete. Ra is varied from 2.5% to 10% with interval of 2.5% by weight of mixed aggregates. Test results indicates that the replacement of Ra by mixed aggregates with low quality crushed sand and sea sand resulted in decrease of slump and air contents due to increased viscosity.

The objective of this paper is to offer the feasibility of premixed type ternary blended aggregates using reject ash(RA), crushed sand(CS) and sea sand(SS) by studying fresh properties of the concrete. RA is varied from 2.5% to 10% with interval of 2.5% by weight of mixed aggregates. Test results indicates that the replacement of RA by mixed aggregates with low quality crushed sand and sea sand resulted in decrease of slump and air contents.

Recently, serious construction site accidents are increasing. At present, the accident rate of the whole industry is 0.5 ('15), while the accident rate of the construction industry is 0.75 ('15), which is 50% higher than the accident rate of the whole industry. In order to reduce the accident rate of the construction industry to the level of the accident rate of the whole industry, there are various methods such as compliance with specifications, drawing and specification, thorough supervision of management, most importantly, it is necessary to recognize that the safety management of construction work is not the work of the builder only, and that it is the task of all participants of the construction work (contractor, designer, builder, construction management). In addition, it should be based on the institutional part to support that. As a part of this, design for safety was introduced to prevent disasters occurrence in construction work. Design for safety was introduced to prevent disasters occurrence in construction work. In this study, we intend to elaborate domestic and overseas institutions and revitalization plans.

In this research, in order to improvement the performance of the two-component mixed aggregate mixed with fine granite fine aggregate and seawater, the examination of the effect of reject ash on the cement mortar according to the change of substitution rate was done. As a result, it was found that the effect of improving the compressive strength is more effective when the rejection ash is replaced by 5% in the mixed aggregate than in the case of using the high quality aggregate.

In this research, the investigation of the temperature condition of reinforcing bars under laboratory temperature and outside temperature conditions in the insulation curing method of Korean-Chinese concrete bubble sheet to examine the suitability of the bubble sheet curing method. As a result, the heat of hydration of the concrete on the wall part affects the exposed reinforcing bars to delay the temperature drop at the part where the bubble sheet is not laid

Recently, serious construction site accidents are increasing. At present, the accident rate of the whole industry is 0.5 ('15), while the accident rate of the construction industry is 0.75 ('15), which is 50% higher than the accident rate of the whole industry. In order to reduce the accident rate of the construction industry to the level of the accident rate of the whole industry, there are various methods such as compliance with specifications, drawing and specification, thorough supervision of management, most importantly, it is necessary to recognize that the safety management of construction work is not the work of the builder only, and that it is the task of all participants of the construction work (contractor, designer, builder, construction management). In addition, it should be based on the institutional part to support that. As a part of this, design for safety was introduced to prevent disasters occurrence in construction work. Design for safety was introduced to prevent disasters occurrence in construction work. In this study, we intend to elaborate domestic and overseas institutions and revitalization plans.

In this research, in order to improvement the performance of the two-component mixed aggregate mixed with fine granite fine aggregate and seawater, the examination of the effect of reject ash on the cement mortar according to the change of substitution rate was done. As a result, it was found that the effect of improving the compressive strength is more effective when the rejection ash is replaced by 5% in the mixed aggregate than in the case of using the high quality aggregate.

In this research, the investigation of the temperature condition of reinforcing bars under laboratory temperature and outside temperature conditions in the insulation curing method of Korean-Chinese concrete bubble sheet to examine the suitability of the bubble sheet curing method. As a result, the heat of hydration of the concrete on the wall part affects the exposed reinforcing bars to delay the temperature drop at the part where the bubble sheet is not laid.

The purpose of this study is to present a suitable maintenance guide or plan for future small scale vulnerable facilities by analyzing the investigation data collected through the safety inspection. For this, we examined about 3,301 buildings. From a number of defects, damages associated with the safety and durability of building were preferentially analyzed.

The aim of the research is suggesting the curing method and selection of surface-covered curing materials with the goal of achieving non-cracking concrete by applying on the actually constructed top slab of the apartment and comparing the surface covering method using single-layered white bubble sheet with the surface covering method using polyethylene film.

In construction sites there are many cases that concrete is cured in a dry condition, without being moistured, after form have been removed. Consequently such curing condition causes cracks on concrete. In this study is to observe when applied ERCO(Emulsified Refined Cooking Oil) coating on concrete surfaces after removal of form, affects water evaporation and Shrinkage of high-strength mortar.

The purpose of this study is to utilize the basic data and to propose the service life prediction method of RC structures. For this, we analyzed the existing programs used for service life prediction software in international such as U.S, Japan, Greece and Canada. The results of Analysis, the prediction of carbonation and chloride were common items in respectively programs.

As the usage of supplementary additives such as blast furnace slag and fly ash for concrete was increased, the carbonation of concrete has been a problem. Hence, in this research, as a solution of carbonation of the high-volume supplementary additive concrete, the effect of waste oil based liniment on carbonation and chloride resistivity was analyzed when it applied on the surface of the concrete.

The purpose of this study is to investigate the correlation of the ultrasonic velocity and the compressive strength according to the strength zone. According to results of the experiments, in the results of including early age compressive strength, correlation of compressive strength and ultrasonic velocity was high. It is determined that Ultrasonic velocity in the high strength section is not significantly affected by moisture.

This study is a basic research for estimating compressive strength of the high strength concrete by utilizing mechanical impedance method. Here, an experiment was performed to investigate the correlation and analysis about the actual compressive strength and the index value deduced by mechanical impedance method. Later, if an additional verification is carried out, it is determined to be possible to use a mechanical impedance method in the field.

The objective of this paper is to investigate the effect of spreading time of waste cooking oil (WCO) on durability of high volume blast furnace slag concrete. Carbonation and resistance to chloride attack were measured according to spreading time of WCO. WCO was spreaded on the surface of the concrete with different curing condition after demolding. Blast furnace slag with 60% was incorporated into concrete with 45% of W/B. Test results indicated that carbonation and penetration resistance of chloride attack had favorable results with the condition of 28days water curing and spreading WCO.