This paper presents the tensile strength characteristics of glass fiber reinforced concrete. The tensile strength and flexural strength of glass fiber reinforced concrete are investigated with various mixing ratio of glass fiber. The tensile strength increases 55∼620% and the flexural strength increases 55∼77%.

This study is to perform experiment of concrete according to addition of blast furnace slag powder and sulfur activator dosages. Blast furnace slag powder used at 30, 50, 80% replacement by weight of cement, and liquid sulfur additives was chosen as the alkaline activator. As a result, it should be noted that the sulfur alkali-activators can not only solve the disadvantage of blast furnace slag concrete but also offer the chloride resistance of alkali-activated blast furnace slag concrete to blast furnace slag concrete.

The study was conducted to evaluate the penetration performance of Surface Protection Material(SPM) according to the particle size distribution of fine aggregate. The fine three types of aggregates were used, and the amounts of SPM were applied 0.13, 0.25, 0.36, and 0.51 kg/㎡. Test results indicated that the penetration depth of SPM were improved with increasing the amounts of application of SPM. And The penetration depth of SPM were improved with increasing the percentage of passing weight of size of sieve between 0 and 1.25mm.

In this paper, the mechanical properties of GGBFS concrete according to the replacement ratio of electric arc furnace oxidizing slag fine aggregate was evaluated. As the replacement rate of EOS fine aggregate increased, the amount of slump and air content decreased. In addition, EOS concrete increased the initial compressive strength, but, it tended to decrease at 28 days.

Recently, high-performance and high-fluidity concrete have been studied and developed because high-rised build is constructed. An early-age properties of these concretes have been studied and developed bacause of comparing existed concrete. This study proposed non-destructive method as electrical resistivity measurement, which evaluates setting time of cement-based materials. An assessment of the effect on the setting time was studied on the addition of a superplasticizer to delay the setting time and the curing temperature to promote the setting time. 6th of samples prepared mortar according to adding superplasticizer(PNS) or curing temperature and measured the electrical resistivity during 24 h. As the results, mortars which curing higher temperature were promoted rising time which is setting time in the electrical resistivity, also mortars which adding superplasticizer were retard rising time.

This study is to analyze the causes of damage on additional facilities in road. In this study, lab test was performed using field core sample. The result of The compressive strength of concrete is met with the design regulations. However, the chloride content of in concrete increased up to 2cm. The microstructure and reactant analysis identified an expanding substance on the surface. However, as the time increases, the depth is expected to be deep.

In this study, the cement composites incorporating Carbon Nanotube(CNT), Carbon Black(CB), and Carbon Fiber(CF) of 0.5, 1.0, and 1.5% of binder weight were evaluated to provide conductivity. In order to achieve this, compressive strength and electrical resistance were measured. As a result, the conductivity of cement composites incorporating CNTs was more sensitive than that of cement composites containing CB and CF.

This study evaluated the fiber orientation and distribution fiber in the beam members of cementitious materials using conventional and tapered nozzles. For this purpose, the specimens with 10cm × 10cm × 30cm were vertically cast to evaluate the fiber orientation and distribution coefficients on the cutting plane. Compared to the conventional nozzle, the tapered nozzle showed an improvement in the fiber orientation and distribution in the beam member.

This paper presents the mechanical response of concrete composites subject to extreme loadings including blast. In general, the dynamic strength of the concrete was greater than the static strength of the concerete so the dynamic increase factor (DIF) was defined as a ratio of the dynamic strength to the static strength and greater than one. Since the DIF was a function of strain rate, it was hard to apply the DIF to the analysis and/or design of concrete. Therefore, the new

The purpose of this study is to investigate the effect of long - term deterioration factor of 12 months on 6 kinds of coating waterproofing materials (polyurethane 1, 2, acrylic rubber, polyurea, rubber asphalt, cement - As a part of the study to characterize the performance change in material aspect, the research was carried out on the tensile strength of the polyurea coating waterproofing material against the performance change in the long term exposure to the chemical erosion environment. As shown in the test results, it was mainly performed in an acidic environment, and it can be confirmed that polyurea is not resistant to acid. In the alkali and sodium chloride environment, the tensile strength after immersion for the last 12 months showed a decrease in strength within about 10% of the initial tensile strength, and it was confirmed that the resistance was excellent in an alkali environment.

In this study, the temperature correction strength (Tn) was conducted to propose (Tn) according to the management age of structural concrete that is separated from the average curing temperature of 4°C to 17°C in cold conditions. After reviewing the strength difference of the concrete using fly ash as a combined material at W/C 50%, the temperature correction strength (Tn) is proposed. The temperature correction strength was proposed to compensate for differences with standard curing conditions due to decrease in curing temperature from 28th, 42nd, 56th and 91st of the models interpreted as equivalent age methods.

The study examined the difference in activation by using a container (1cm, 3cm) that was different in height from the other time (3 minutes, 6 minutes, 9 minutes) at the same temperature. The activation time and height of the container do not affect the strength.

This paper proposed the measures that to predict changes in the state of the individual tunnels, and maintenance costs during its life cycle by using the big data of tunnel facilities. This is expected to be used to efficiently establish long term maintenance plans for tunnels based on data-based engineering analysis.

This study is to develop a bridge inspection technology through convergence of advanced technologies such as drone technology and hybrid image scanning technology. Through this study, a UAV(Unmanned Aerial Vehicle) user guideline framework for bridge condition evaluation is proposed. It is presented for writing UAV user guideline that is applicate a field of a bridge inspection using this proposal framework in this study.

Recently, there have been many studies to classify the image-based damage of bridge using the deep learning and to evaluate the condition. These attempts are one of the ways to overcome limitations of visual inspection through inspectors, and it is also aimed to reduce the cost of necessary maintenance budget by enabling accurate and rapid damage assessment of rapidly growing old facilities and difficult parts of visual inspection. However, it is possible to classify and quantitatively express simple damage (one damage classification such as cracks) with image information (big data) of bridges, but classification and quantification of complex damage can be done by using one deep learning is a limit. Therefore, this study presents considerations and a method to be used for damage detection on the image basis using deep learning.