• Resources Recycling
• /
• v.10 no.1
• /
• pp.16-24
• /
• 2001

In this study, various mechanical properties of concretes employing waste concrete as aggregate were examined. These concretes were obtained by mixing seven types of aggregate for different ratios. So, the experimental variables are the kinds of aggregates (some different aggregate compositions) and W/C ratio (0.40, 0.45, 0.50). From experimental results, the reliable regression analysis equations between compressive strength and various experimental data for recycled aggregate concrete are presented. Consequently, this study was accomplished to investigate basic engineering properties of recycled aggregate concrete using waste concrete.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.797-800
• /
• 2008

To decrease the usage of cement, the pozzolan reaction materials are used as a mineral admixture. Hwang Toh which is broadly deposited in Korea is well known as a environment friendly material and the activated Hwang Toh which has the property of pozzolan reaction is practically used as a mineral admixture of concrete. PET fiber which is made by recycled PET bottle controls micro crack in concrete. But the study about concrete mixed with reinforcing fiber is not enough and the property of Hwang Toh concrete mixed with PET fiber is more complicated case. So this study performed drying shrinkage experiment to analyse mechanical property of Hwang Toh concrete mixed with PET fiber.

• Magazine of the Korea Concrete Institute
• /
• v.10 no.4
• /
• pp.163-169
• /
• 1998

The strength and freeze-thaw test were carried out in order to use recycled aggregate as crushed aggregate in concrete. The recycled concrete had a lower flexture and compressive strengths than ordinary concrete, but the inclusion of fly ash shows similar results in both concretes. The resistance of freeze-thaw was strongly influenced by W/C ratio, content of recycled aggregate and fly ash, and it was also found that the resistance was higher when W/C ratio and fly ash content was lower. and was superior when replacement level of recycled aggregate reached to 80%.

• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2003.10a
• /
• pp.129-133
• /
• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2002.10a
• /
• pp.39.1-39
• /
• 2002

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.11a
• /
• pp.47-48
• /
• 2014

This study is to hydration property of low carbon type recycled cement from waste cementitious powder and cement raw materials. Waste cementitious powder possible to low carbon type recycled cement in small part of additive materials. Also, low carbon type recycled cement using waste cementitious powder is suitable for low heat type cement.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1990.10a
• /
• pp.95-100
• /
• 1990

The behavior of short span filled spandrel arch bridge of 10 and 21 m span with various axis line, rise and backill height were investigated under the design loads(self weight, earth pressure, temperature load, live load, etc). Even though the behaviors of arch were known as relatively complicated, the followings can be concluded within the limits of this study. The design value of arch bridge increase as the rise decreases, the effects of temperature load become dominant for the design of arch bridge, and governing design factors are occured at springing.

• Journal of the Korea Concrete Institute
• /
• v.17 no.1 s.85
• /
• pp.19-25
• /
• 2005

Recycling of waste materials in the construction Industry is a useful method that can cope with an environment restriction of every country. In this study, synthetic lightweight aggregates are manufactured with recycled plastic and fly ash with 12 percent carbon. Nominal maximum-size aggregates of 9.5 mm were produced with fly ash contents of 0, 35, and $80\%$ by the total mass of the aggregate. An expanded clay lightweight aggregate and a normal-weight aggregate were used as comparison. Gradation, density, and absorption capacity are reported for the aggregates. Five batches of concrete were made with the different coarse aggregate types. Mechanical properties of the concrete were determined including density, compressive strength, elastic modulus, splitting tensile strength, fracture toughness, and fracture energy. Salt-scaling resistance, a concrete durability property, was also examined. Compressive and tensile strengths were lower for the synthetic aggregates; however, comparable fracture properties were obtained. Relatively low compressive modulus of elasticity was found for concretes with the synthetic lightweight aggregate, although high ductility was also obtained. As nv ash content of the synthetic lightweight aggregate increased, all properties of the concrete were improved. Excellent salt-scaling resistance was obtained with the synthetic lightweight aggregate containing 80 percent fly ash.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.3
• /
• pp.276-284
• /
• 2022

In this study, performance evaluation and rheological characteristics were analyzed for recycling the fine powder of nuclear power plant dismantled waste concrete as a solidifying agent for radioactive waste disposal. The radioactive concrete fine powder was used to prepare a simulated sample, and the test specimen was prepared using Di-water, CoCl₂, and 1 mol CsCl aqueous solution as mixing water. Regardless of the aggregate mixing ratio and the type of mixing water, it satisfies the performance standard of 3.45 MPa for compressive strength at 28 days of age. All specimens satisfied the criteria for submersion strength, and the thermal cycle compressive strength satisfies the criteria for all specimens except Plain-50. As a result of evaluating the rheological properties of the solidifying agent, it was found that the increase in the aggregate mixing rate decreased the yield stress and plastic viscosity. The leaching index for cobalt and cesium of all specimens was 6 or higher, which satisfies the standard. In order to secure the stable performance of the solidifying agent, it is considered effective to use 40 % or less of the aggregate component in the solidifying agent.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.10a
• /
• pp.245-248
• /
• 1999

In our standard specification, the specific provision of steel fiber pavement concrete didn't describe yet. The purpose of this study presents criteria of recycled aggregate steel fiber pavement concrete including standard crushed stone steel fiber pavement concrete. This study examined a lot of factors which influence consistency of SFRC(Steel Fibre Reinforced Concrete) including crush stone and recycled aggregate. According to this examination, this study decided optimum S/α and W which are essential to pavement concrete mix proportion. Come to the conclusion, this study is expected to effect economically in recycling of resources and bring to affirmative result in aspect of environment.