• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.163-164
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• 2010

Ultra high performance concrete (UHPC) is a relatively new cementitous material, which has been developed to give significantly higher material performance than conventional concrete or engineered cementitious composites. In this study, reverse analysis of notched UHPC beam was conducted according to the experimental result of load-displacement. Conclusively, tensile strength vs. CMOD (Crack Mouth Opening Displacement) was calculated as an approximated method for the direct tensile strength estimation.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.573-576
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• 2004

High performance SFRC composed of mira-sized ultra fine particles is characterized by high strength, high ductility and excellent durability. therefore many researches about materials based on new composition like this are performed recently. many researchers have reported that adding steel fiber to concrete improved its tensile and flexural strength significantly. the main objective of this research is to examine the effect of adding steel fiber on the tensile strength of high performance SFRC. variables considered in this study are w/c ratio and fiber volume fraction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.37-38
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• 2011

This study is to analyze and compare improved curing sheet with blue sheet in order to verify the performance related to tensile stress. As results, it is confirmed that improved curing sheet(MP+BBS1) is better than the blue sheet at using field already. Synthetically, curing sheet improved by MP is analyzed to be available instead of the original because it is superior to tensile stress.

• Journal of the Korea Institute of Building Construction
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• v.1 no.2
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• pp.165-173
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• 2001

This study examinated the application in construction field and the development of waterproofing material system by the spray water-soluble rubber asphalt to solve the problems of synthetic polymer sheet and gio membrane(A mat sheet of Bentonite) that had been used domestic waterproofing material in advance. As the result of study, characters of study water-soluble rudder asphalt are the follows: 1) The amount of water absorption was '0.06'g and the seepage quality was '0'g in result. 2) The tensile strength was about 30.7kgf/$\textrm{cm}^2 and the elongation was about 72.4% in result. 3) After reliance of temperature test had been ended, the tensile strength was about 72.4kgf/$\textrm{cm}^2 in low temperature and about 30.7kgf/$\textrm{cm}^2 in normal temperature. 4) After acid and alkaline treatment had been ended, the tensile strength was about 19.7kgf/$\textrm{cm}^2$ and about 21.9kgf/$\textrm{cm}^2 in result. 5) After chlorine ion treatment had been ended, the tensile strength was 28.5kgf/$\textrm{cm}^2$ and the elongation was 250% in result. 6) The impact performance was subsided at 1.5m height. 7) After promotion weathering had been ended, the tensile and elongation was about 26.0kgf/$\textrm{cm}^2, 214% in result. So, this study can propose the spray water-soluble rubber asphalt to satisfy the and durability of waste filled land.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.255-261
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• 2019

The purpose of this study is to investigate effects of types of synthetic fibers on mechanical properties of alkali-activated slag composite. Materials and mixture proportion for matrix are determined, and the compressive strength, tensile performance, and cracking patterns of three composites reinforced by polypropylene, polyvinyl-alcohol, and polyethylene fibers. From the test results, it was observed that polyvinyl-alcohol fiber-reinforced composite and polyethylene fiber-reinforced composite had similar tensile performance. On the other hand, polypropylene fiber-reinforced composite showed low tensile performance. And it was exhibited that other factors except tensile strength and aspect ratio of fiber influence significantly tensile behavior of composite.

• International Journal of Concrete Structures and Materials
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• v.8 no.4
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• pp.301-307
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• 2014

Rice husk ash (RHA) is classified as a highly reactive pozzolan. It has a very high silica content similar to that of silica fume (SF). Using less-expensive and locally available RHA as a mineral admixture in concrete brings ample benefits to the costs, the technical properties of concrete as well as to the environment. An experimental study of the effect of RHA blending on workability, strength and durability of high performance fine-grained concrete (HPFGC) is presented. The results show that the addition of RHA to HPFGC improved significantly compressive strength, splitting tensile strength and chloride penetration resistance. Interestingly, the ratio of compressive strength to splitting tensile strength of HPFGC was lower than that of ordinary concrete, especially for the concrete made with 20 % RHA. Compressive strength and splitting tensile strength of HPFGC containing RHA was similar and slightly higher, respectively, than for HPFGC containing SF. Chloride penetration resistance of HPFGC containing 10-15 % RHA was comparable with that of HPFGC containing 10 % SF.

• Land and Housing Review
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• v.10 no.4
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• pp.51-59
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• 2019

The government is encouraging the notice of obligatory reclaimed asphalt as a result of the economic and social positioning of green growth to reduce the amount of waste resources and to solve natural resource problems by recycling continuously generated waste resources. However, it is necessary to develop application guideline for each application to apply reclaimed asphalt to the site because quality control of the reclaimed asphalt is difficult and the specifications are ambiguous as well. Therefore, in this study, the mix design, quality test, performance test, and finite element analysis about reclaimed Asphalt Pavement were conducted to develop application guideline for reclaimed hot asphalt. The mix design was carried out for the comparative general hot mix asphalt mixture, the reclaimed hot mix asphalt mixture using the additive, and the reclaimed hot mix asphalt mixture without the additive. Indirect tensile strength and tensile strength ratio tests were used to characterize the reclaimed hot mix asphalt mixture. Using the results of dynamic modulus test and FWD test for KPRP analysis and finite element analysis, the performance life was evaluated for general pavement and pavement using recycled aggregate. Finally, the life cycle cost analysis was used to compare and analyze the economics of reclaimed asphalt concrete pavement.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.4 s.193
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• pp.93-101
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• 2007

Aluminum alloy which is one of the light materials has been tried to apply to light weight vehicle body. In order to do that, welding technology is very important. In case of the aluminum laser welding, the strength of welded part is reduced due to porosity, underfill, and magnesium loss. To overcome these problems, laser welding of aluminum with filler wire was suggested. In this study, experiment about laser welding of AA5182 aluminum alloy with AA5356 filler wire was performed according to process parameters such as laser power, welding speed and wire feed rate. The tensile strength was measured to find the weldability of laser welding with filler wire. The models to estimate tensile strength were suggested using three regression models and one neural network model. For regression models, one was the multiple linear regression model, another was the second order polynomial regression model, and the other was the multiple nonlinear regression model. Neural network model with 2 hidden layers which had 5 and 3 nodes respectively was investigated to find the most suitable model for the system. Estimation performance was evaluated for each model using the average error rate. Among the three regression models, the second order polynomial regression model had the best estimation performance. For all models, neural network model has the best estimation performance.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.5
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• pp.125-132
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• 2019

Ultra-high performance concrete (UHPC) has high compressive and tensile strengths due to the particle packing, and its ductile behavior can be ensured by utilizing steel fibers. However, since the UHPC members exhibit different characteristics of crack behavior and tensile behavior from normal concrete, the tension stiffening and cracking characteristics of the UHPC should be accurately modeled for the design and analysis of the UHPC members. In this study, uniaxial tension tests was conducted on the UHPC members with strands, where the test variables were diameter and reinforcing ratio of strands. Detailed analyses were also conducted to identify the tensile characteristics and crack behavior of the UHPC members. By comparing the test results with current code provisions and other models proposed by existing researchers, their applicability for estimation of crack behavior of the UHPC members was examined.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.455-461
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• 2018

The purpose of this study is to evaluate the tensile strength performance of the polyurethane coating material used as the waterproofing material in concrete structures. A linear regression equation is proposed to establish a correlation on the tensile strength of polyurethane coating membrane against periodic exposure to chemical degradation. The polyurethane film membrane showed a minimum strength of 23% to a maximum of 38% when subjected to chemical degradation. The elongation rate showed a relation with the tensile strength deterioration rate of at least 15% to 22% at maximum, and the proposed regression equation could be used to predict the degree of performance change of the polyurethane coating membrane under chemical degradation condition.