This paper was evaluated biological properties of Magnesia cemntitious composites using SAP as a basic study for development to biological panels. Biological properties were evaluated for pH, moisturizing, and surface roughness.

This paper evaluates analytically the flexural behavior of steel fiber reinforced concrete (SFRC) notched beams according to the tensile strength of steel fiber. For this purpose, compressive strength and bending tests of SFRC applying steel fibers with tensil strength of 1,200 and 1,600 MPa was conducted. Strain hardening behavior was observed when using high tensile strength steel fiber. Compression and tensile models were established through test results. For the tensile model, hordijk model and trilinear model were analyzed and compared. The results of analysis showed good agreement when using trilinear model.

In this study, the purpose of this study was to develop concrete structural walls including the functions of the barrier and EMP shielding performance as the concrete structure itself. Mix of highly challenging metal fibers in super-high strength concrete. The EMP measurement frequency was evaluated for EMP card performance using a waveguide measurement method in the range of 0.8 GHz to 1.0 GHz. Performance evaluation shows that steel fiber has an increased compression strength and shielding effect as amount of mixing increases. In addition, shielding performance increased due to the increased thickness of the specimen. Therefore, it is judged that steel fiber is a good blend for shielding effects.

In this paper, the flexural behaviors with substitution ratio of heavyweight waste glass are compared and evaluated in reinforced concrete members. From the results, when the heavyweight waste glass was used as the fine aggregate, the yielding load (Py) and maximum load (Pu) were less affected. However, the load capacity of the RC member was gradually reduced on the large deformed stage when all of the fine aggregate was replaced by heavyweight waste glass.

In this study, the properties of mortar substituted heavyweight waste glass were evaluated. From the results, the flow value and density increased as the substitution ratio of heavyweight waste glass increased, and compressive and flexural strength decreased.

This research provides the baseline data for choosing the inorganic/organic hybrid material as the repairing solution by analyzing its efficiency in securing high vibration resistance and very low permeability. As a result of analysis of the mechanical properties of hybrid composite mortar, the strength increased with age. Therefore, it is considered that an inorganic binder having a certain amount or more is required for high strength development.

This thesis will provide the baseline data of a suitable road repairing solution by analyzing the freeze-and-thaw resistance of inorganic-organic hybrid mortar. The resilience of polymer mortar and high-elastic mortar to freeze thaw resistance showed that the high-elastic mortar showed excellent resistanc

The rate of autogenous shrinkage (AS) development is a fundamental factor that highly influence the crack risk in low water cement mortar. Internal curing (IC) by using SAP has been used to reduce the AS in low water cement mortar and consequently mitigates the high risk of early-age cracking. Super absorbent polymers (SAP) supply additional IC water for hydration of mortar and as a result the effect of self-desiccation was minimized when the amount of internal water reduced. A series of autogenous shrinkage tests were performed considering two different SAP particle sizes in a constant curing temperature and humidity. The results indicated that IC method by using SAP fundamentally solved the problem of autogenous shrinkage in a low water cement ratio mortar.

Resently, sargassum honeri, which has flown into the Korean coast, has become a serious problem due to the serious damage to domestic aquaculture and fishery. The purpose of this study is to utilize sargassum honeri containing alginic acid as a natural polymer material in cement mortar for repairing structures. The experimental results show that the flow of mortar tends to decrease as the incorporation rate of biopolymer increases.

In this study, it evaluate the impact resistance of UHPC by repeated impact. smooth steel fiber and polyvinyl alcohol fiber were reinforced in UHPC respectively. Overall, the impact resistance of the specimens reinforced with 0.4vol.% PVA fiber was high, and the crater diameter was small in specimens using 13mm fiber.

The purpose of this experimental study is to develop an waterborne silicon acrylic top finishing material of car parks. The gas toxicity test was conducted in order to provide fundamental data for developing the material by implementing modified polyamide resin. The outcomes were satisfied by the quality standard regarding elapsed mean stop times of mice which is prescribed in KS F 2271. As conclusion, this study confirmed that the developed finishing material could be an optimum material capable of applying for car parks’ deck.

The purposes of this study is to evaluate the adhesion in flexure and adhesion in tension between old-plain cement mortar and new-polymer cement mortar that has been widely used as finishing and repairing materials of RC structures. From the test results, the adhesion in flexure and adhesion in tension of polymer-modified mortar to plain cement mortar are much higher than that of plain cement mortar, and are increased with increasing polymer-cement ratio. The maximum strengths show at polymer cement mortar using EVA dispersion, and those are about 1.69 and 2.10 times respectively, plain cement mortar.

A large amount of CRT waste has been generated due to the interruption of analog broadcasting in 2012. In particular, CRT glass has been pointed out as a cause of environmental pollution because it contains a large amount of heavy metals such as lead for electromagnetic shielding. In this study, the electrical resistivity of mortar specimen using CRT waste glass as fine aggregate was measured to investigate the relationship between electrical resistivity and shielding characteristics.

The heavyweight industrial waste was used as concrete ingredient instead of natural aggregate, however, design standard did not consider effects of heavyweight aggregate on flexural strength. Therefore, in this paper, correlation between compressive and flexural strength of concrete using industrial was compared. From the results, compressive strength and flexural strength decreased with industrial waste increasing. And, it was shown that the test results of flexural strength were higher than the predicted value from design standard.

The purpose of this study is to compare the compression strength of gypsum substituted mortar with that of mortar. After replacing the cement with the loess, a portion of the remaining cement was replaced with gypsum to make specimens. When the gypsum is replaced, the strength of all the specimens is lower than that of the standard specimen. It is necessary to use a long-term strength mixed material to replace this.

This study is a basic study to CGS, which originates from the IGCC, as fine aggregate for concrete. The study measured density, water absorption ratio, solid volume percentage for grain shape, fineness modulus, grading curve of physical properties of fine aggregate. As a result, the density and solid volume percentage for grain sheet were found to be satisfactory in the aggregate for content (KS F 2527).Water evaluation ratio, fitness modulus, and grinding curve did not meet KS standards. Therefore, it is deemed necessary to adjust the grain size through sieving in case of fineness modulus and grinding curve.

This study investigates the effects of compressive strengths on mechanical properties of concrete with compressive strengths of 40 and 80 MPa. In this study, The steel fiber an aspect ratio of 64 and a tensile strength of 1,600 MPa used. As the result, There are no significant effect of fiber tensile strength on mechanical properties of normal strength SFRC. For high strength SFRC, Specimen with high strength fiber have superior performance then that with normal strength fiber.

Chloride penetration into concrete is the main cause of the corrosion of steel in concrete structures exposed to chloride-rich environments. As a preventive or remedial method, surface treatments on concrete have been increasingly applied to both new and existing concrete structures to combat this problem. So far, knowledge of how a surface treatment reduces chloride diffusion is limited and the relationship between chloride diffusion resistance and surface treatment parameters, such as thickness, porosity and diffusion coefficient, has not been quantitatively identified. In this paper, chloride ion penetration modeling is performed to predict the service life of the surface treated concrete.

In this study, the behavior of composite concrete under low velocity impact with various temperature condition was assessed. The displacement-time curve from the experimental device impactor was utilized. The results showed that there is a significant change in the ductility when composite material is used at different temperature condition.

Experimental results show that the maximum temperature of the floorboard surface is 1/2 level compared to the hot water temperature of 80℃, which is circulated by hot water heating. And the part above 10mm above the surface of the floorboard was low as 1/3 level. Therefore, in order to improve the heating efficiency of the room where the flooring is applied to the hot water heating, the thermal conductivity of the flooring material should be improved as well.