• Journal of the Korea Concrete Institute
• /
• v.13 no.5
• /
• pp.423-429
• /
• 2001

In this study, strength characteristics of concrete specimens subjected to horizontal continuous vibration during initial curing were investigated. As experimental variables, vibration velocity(0.25, 0.5, 1.0, 2.0, 4.0 kine) and vibration time(3, 6, 12, 24 hrs) were used. Density and segregation of the specimens were also investigated. Vibrating was started soon after placing, and strengths investigated consist of compressive strength, splitting tensile strength, and bond strength. Strengths decrease were hardly occurred at 0.25 kine vibration velocity regardless of vibration times and all strengths were increased for 3 hrs vibration at 0.5 kine vibration velocity. Density was increased for all specimens due to the vibration and there was no serious segregation under even 4 kine vibration velocity.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.5
• /
• pp.413-419
• /
• 2016

In the cold-weathering concrete construction, it is important to ensure stable strength development of concrete in a low temperature environment. In this study, Non-curing cement(NCC) using the classified high fineness cement and self-heating powder was investigated for stable strength development without curing in a low temperature environment (less than $0^{\circ}C$). The actual size Mock-Up tests by various cement type and curing condition are performed to evaluate the strength development and hydration heat of concrete.

• Magazine of the Korea Concrete Institute
• /
• v.7 no.2
• /
• pp.126-135
• /
• 1995

Thermal cracks are occured when thermal stress due to the hydration of cement exceeds the tens~le strength of concrete. Since crackmg causes poor durability of concrete, the effect of ther ma1 cracking should be includod for the design and construction of massive concrete structures. In this study, an experiment is performed for the investigation of time dependent thermal stress history. In order to evaluate thermal stress. two methods are employed. One 1s the evaluation method of thermal stress based on the measurement from embedment stram gauge with non-stress strain gauge and the other 1s based on the measurement from concrete stress gauge. As a result of this study, the value corrected by the former shows good agreement with the latter. The validity of the proposed method for the evaluation of thermal stress 1s explored.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.150-154
• /
• 1998

Database schema is designed to accumulate the literal information automatically such as reinforced concrete design specifications. Sentence of design knowledge with literal data, numerical data, and symbols have analyzed manually. Finally, the proposed method has been shown that by proper design of the database schema of knowledge information as a function of design rule.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.142-145
• /
• 1998

The purpose of this study is to estimate lateral formwork pressure controlled by super-workable fresh concrete using prototype structrues such as, tall wall, retaining wall, and beam quantitativly. As a result of this experiment, a function which can be used to design a formwork system and to predict formwork pressure curve is formulated.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.119-123
• /
• 1998

New design automation method of R/C beam based on the finite element method and the nonlinear truss model approach has been presented. The proposed method can substitute inaccurate existing method, which has limitation in its application, provide accurate and efficient design results for any type of R/C beam.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2002.10a
• /
• pp.161-164
• /
• 2002

This study was performed to find out the regression function to calculate the modulus of elasticity of concrete mixed by river coarse aggregate. The distribution of the group of core strength made a normal curve and the effect factor in the modulus of elasticity was 0.97 at the concrete compounded by river coarse aggregate.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2001.10a
• /
• pp.171-175
• /
• 2001

The quality control application of concrete are one of the most important problems to be considered in cold weather concreting. And, the construction is going on now Therefor, the major test variables are compressive strength of concrete, curing method and volume of air content. This shown to be possible to construction and quality control of cold weather concreting in field.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.219-224
• /
• 1999

In this study New design automation method of R/C structure based on the finite element method and the analogy evolution ary procedure was developed . This system is the efficient tool to support Reinforcement Arrangement of R/C structure. The anology evolutionary procecure is similar to the evolutionary procedure proposed by Xie and Steven.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.212-218
• /
• 1999

In this study , Computer programs for the optimum and automation desgin of reinforced concrete box culvert were developed. It was shown that even though the strarting points and optimization method are different the objective function and optimum design variables converge to a value within a close range respectively, and consequently the optimum design program developed in the study is reliable and stron. 3D-design drawing can be drawn using automation desgin computer program developed in this study.