This research investigated the effect of fiber orientation on the tensile strength of PVA, PE and Basalt fiber. Test results showed that the fiber strength reduction coefficients of PVA, PE, and Basalt fibers were 0.171, 0.485, and 1.54, respectively.
In this study, Analyzed characteristic about permeability cold-mixed recycled asphalt concrete using waste asphalt concrete and MMA. As a result, porosity was 19.4% and permeability coefficient was 0.4cm/sec. Marshall stability test had the highest MMA 4% and a hardener 3%.
In this study, hydration heat analysis of ternary blended concrete using mock-up structure was conducted in order to evaluate the temperature rise and crack index. The results of the analysis of hydration heat, it was found that it was convenient to obtain the minimum crack index and temperature rise of 3:5:2 mixing.
Based on the paper study of recycled aggregates production method and registrated patents , it was found that the structural use of recycled aggregates was few. And it was caused by high production costs and lack of researches.
The purpose of this research is to investigate characteristics of cementitious composites containing lathe scrap to use it as a alternative materials of steel fiber. For this purpose, the cementitious composites containing lathe scraps were made according to 5mm, 10mm, and 20mm in lengths for their widths of 2mm and 4mm, respectively. It was observed from the test result that the cementitious composites containing lathe scraps were most largely increased than plain mortar in the compressive and flexural strengths when its width is 2mm and its length is 5 to 10mm.
Dry shrinkage of concrete is occurred due to the cement hydration and water evaporation from early ages, and it induces crack of concrete. In this study, shrinkage according to sand-aggregate and water-binder ratio were compared with the existing prediction models. From the results, when sand-aggregate ratio and unit water content increase, dry shrinkage of concrete increase. But, it showed that existing prediction models do not reflect shrinkage of concrete, well.
As the industrialization is rapidly growing and the quantities of heavy weight waste glass have been quickly increased but the most of them are not recycled. The heavy weight waste glass have been treated by illegal dumping or being buried in landfills. And, it is caused some problem such as the environmental pollution. So, it is needed to investigate the possibility of recycling of heavy weight waste glass as concrete material ingredient.
In this paper, the mechanical properties of mortar substituted the crushed waste glass as fine aggregate are evaluated. From the results, when waste glass substitution ratio increase, fluidity and specific gravity increase. However, the compressive strength and flexural strength decrease. So, the mechanical properties of mortar are significantly affected by waste glass substitution ratio.
In this study, cement-based accelerators, which have an advantage of preventing early frost and in developing early strength in cold-weather. Then, whether it can be secured the operating time by controlling the response time in early-stage and can be developed due to the accelerator's function, as evaluated by testing.
By analyzing the strength of shotcrete mixture with blast furnace slag and confirmed the suitability as subsea tunnel support. As a result, the shotcrete mixture with slag is excellent evaluated in terms of durability compared with existing shotcrete.
In this study, We analyzed for compressive strength and flexural characteristics of high performance fiber-reinforced cement composite according to PAE polymer mixing (HPFRCC). The results of the experiment, the difference in compressive strength and flexural characteristics properties is generated by PAE polymer incorporation. Analysis results showed that improved mechanical properties relative to the polymers when mixed with the PAE.
This research project is to be carried out to propose the methodologies for improving the structural maintenance system by performance concepts consideration. The main contents of this project are performance(Safety, Durability, Serviceability etc) based management methodology. If this project is performed successfully, it is expected that the infrastructures can be effectively managed in Korea.
The durability evaluation method of concrete structures was introduced. It is divided into two parts, one is aging environment, and the other is aging development evaluation which including time factor. This method will be helpful to estimate the synthetic durability of the SOC facilities.
Steel structure such as steel bridges are severely affected by the corrosion, and thus has to be maintained by periodic inspection and repetitive painting. In this study, existing empirical models for the degradation of coating are reviewed which is used for evaluation of corrosion, and in addition applied to definition of the state inspection criteria and condition rating by further research.
This study was performed to select the performance-based evaluation items of concrete retaining wall. This study used Delphi Technique. As a result of survey, this study gained 17 condition assessment items and 7 safety evaluation items at final round. The results will be utilized as the basis for the performance-based evaluation.
Since the 1970s, construction projects of SOC infrastructure have began rapidly. therefore, it is expected that the proportion of infrastructure using for more than 30 years will be increased in an instant. Because an aging infrastructure can greatly damage the national economy and people, maintenance of the infrastructure is essential. In this paper, performance-based evaluation items for maintenance of SOC(Social Overhead Capital) infrastructure and the process of calculating the weights of each items by using the AHP(Analytic Hierarchy Process) method are introduced.
Currently internal harbor and fishing port facilities are being maintained with the "Safety inspection and in-depth safety inspection detailed guideline" This is provided with the evaluation focusing on the safety and durability of the structure, based on the usability are not presented. In this study, we derive the evaluation items of the harbor and fishing port facilities for the transition from the maintenance of the existing system to the performance-based safety and maintenance system.
Evaluation items were deducted by based on literature materials to supplement the evaluation system of rock cut-slope in national road. Delphi survey of experts were conducted to review the final evaluation items. As a result of reviewing the significance through stepwise multiple linear regression, all of deducted items were statistically significant because these had lower P-value than 0.05. And It was confirmed that the items were selected appropriately as they had relatively similar levels of the weight.
South Korea has a soft ground in many areas, and many reinforcing method were used to build the structure on the soft ground. PF method is eco-friendly and secure a bearing capacity by forming a basis of bulbs through mixing the soil and a high-performance "Bindearth", and can control the settlement. Here are we introduce a test case study method through the recent case of the PF.
Current design standards (Korea Highway Bridge Design, AASHTO), the dynamic behavior under the impact loading has not been considered, only considered static force for designing bridge column against vehicle collisions. In this study, vehicle collisions to concrete bridge column were developed with various boundary conditions, and a comparison study of direct impact analysis of vehicle to bridge-column with in-direct impact analysis was performed.
In the recent years, composite beam is now being frequently used not only in reduction of the story height but also saving material quantity. There has been heightened interest in composite beam. In this study, new composite beam was proposed, which composed of H-section and U-section members. Angles were used for shear connectors for composite action. In order to investigate the performance of the suggested composite beam, test programs were carried out to evaluate the composite beam's structural behavior and effectiveness as conducted experiments consist of push-out tests, beam flexural tests and beam-column connection tests.