• Title/Summary/Keyword: concrete object

Search Result 308, Processing Time 0.028 seconds

An Evaluation of the Bond Performance and the Shear Behavior of Concrete Mixed with Hwang-toh (황토를 첨가한 콘크리트의 부착성능 및 전단거동 평가)

  • Jung Yeon Back;Yang Keun Hyeok;Hwang Hey Zoo;Chung Heon Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2005.05a
    • /
    • pp.83-86
    • /
    • 2005
  • The object of this experimental study is to understand the bond performance and the shear behavior of concrete mixed with hwang-toh and blast-furnace slag. Main variables were the compressive strength according to replacement level of hwang-toh and blast-furnace slag. The results revealed that up to 20$\%$ of Hwang-toh the bond and the shear strength were improved.

  • PDF

Fire Performance of Structural Lightweight Aggregate Concrete using PP fiber (PP섬유 혼입 고강도 경량골재콘크리트의 내화특성)

  • Song, Hun;Chu, Yong-Sik;Lee, Jong-Kyu
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.797-800
    • /
    • 2006
  • Normally, Structural light-weight aggregate concrete(LWC) has been main used in high rise building with the object of wight loss. In spite of LWC have the advantage of light-weight, limit the use of strength restrictions by reason that explosive spalling in fire. Especially, LWC is occurred serious fire performance deterioration by explosive spalling. Thus, this study is concerned with fire performance of LWC for the purpose of using PP fibers prevent to explosive spalling. From the experimental test result, LWC is happened explosive spalling.

  • PDF

An Experimental Study on Prediction of Compressive Strength of the In situ Mass Concrete with Fly-ash (플라이애쉬를 혼입한 현장타설 매스콘크리트의 압축강도 추정에 관한 실험적 연구)

  • Khil, Bae-Su;Chae, Young-Suk;Nam, Jae-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.3 no.1
    • /
    • pp.163-169
    • /
    • 1999
  • The object of this study is to compare properties of massive fly-ash concrete with plain concrete. Two concrete mixtures comprising two batch each $1.0m^3$ in volume, were made from ready mixed concrete batch plant. The water-to-cementitious materials ratio was kept constant at 51.4%. Therefore, massive concrete specimen($W800{\times}D800{\times}H800mm$) was cast from ready mixed concrete to analyze history of temperature and core strength properties. Bleeding, time of slump loss and time of setting of the fresh concrete were measured. In order to estimate the properties of massive fly-ash concrete in hardened concrete, non-destructive tests such as rebound hardness, ultrasonic pulse velocity and maturity were performed and analyzed.

  • PDF

A study on the a1gebraic thinking - From the perspective of 'process' and 'object' aspects - (과정-대상 측면에서 본 '대수적 사고' 연구)

  • 김성준
    • Journal of Educational Research in Mathematics
    • /
    • v.12 no.4
    • /
    • pp.457-472
    • /
    • 2002
  • In this paper, we deal with the algebraic thinking from the perspective of ‘process’ and ‘object’ aspects. Generally, mathematical concepts have come from the concrete process. We consider the origin of algebra as the arithmetic calculations. Also, the concept of school arithmetic is beginning from actions or procedures. However, in order to develop the alge- braic thinking and to apply this thinking, we have to see the history of algebraic thinking, and find this duality. Next we investigate various researches relating to the ‘process-object duality’. Theses studies suppose that the concept formation and thinking process should be stared from the process-object duality. Finally, we reinterprete many difficulties in algebra - equals sign, variables, algebraic expressions, and linear equations, the principle of permanence of form- from the perspective of the process-object duality.

  • PDF

A study on the Flexural Behavior of Structural Deck Plate using High-Strength Lightweight Concrete (고강도경량콘크리트를 사용한 구조용 Deck Plate의 휨거동에 관한 연구)

  • 김철환;최명신;안종문;김범조;소병규;신성우
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1998.04b
    • /
    • pp.505-512
    • /
    • 1998
  • The object of this study is investigated to flexural behavior of structural deck plate composite slabs using high-strength lightweight concrete. Test variables are concrete compressive strength (normal weight concrete 210kg/$\textrm{cm}^2$, lightweight concrete 270, 350kg/$\textrm{cm}^2$), topping concrete thickness (70, 75mm when span is 3.4m), deck plate depth (50, 75mm when topping concrete thickness is 70mm and span is 3.4m) and span(3.0, 3.4m). Test results are compared with current ACI Building Code(318-95). The test results are follows ; (1) a value of Ptest/Pcal is 1.27~1.39, (2) a mean value of $\delta$test/ $\delta$ACI is, 0.60 when deflection is reatched to maximam permissible computed deflection (L/360), and (3) ductility index are 3.61~6.85.

  • PDF

An Experimental Study on the Supposed Heating Temperature of Exposed Concrete at High Temperature (고온에 노출된 콘크리트의 수열온도 추정을 위한 실험적 연구)

  • Jang Jea bong;Lee Eui Bae;Cho Bong Suk;Kim Yong Ro;Kwon Young Jin;Kim Moo-Han
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2004.11a
    • /
    • pp.157-160
    • /
    • 2004
  • If concrete structure is exposed to high temperature such as long-term fire, damages affecting partial or whole structure system may occur. Therefore accurate diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the properties of concrete exposed to high temperature are necessary. Especially, the amount of fire damage done to concrete depends on the materials, the standard design compressive strength of concrete, and heated temperature. So, the object of this study is to present data for supposed heated Temperature of deteriorated concrete by fire.

  • PDF

Internal Object Detection Monitoring System in Reinforced Concrete Structure using UWB-RF (UWB-RF를 이용한 콘크리트 구조물의 내부 물체 검출 모니터링 시스템)

  • Park, Dae-Hyuck;Kang, Eui-Sun
    • Journal of Digital Contents Society
    • /
    • v.18 no.7
    • /
    • pp.1457-1464
    • /
    • 2017
  • This paper is to introduce the a system which monitors and detects the object position in reinforced the concrete structure using UWB-RF. This system is able to check any changes in the inside of the concrete structure using its penetration and reflection characteristics and it can also numerically measure the position of rebar in the concrete structure. For the verification of the performance of this system, we set up the internal compositions of concrete in 3 different types of test-bed. On the other hand, for the measuring of the location of rebar, which varies depending on the type of structure, the software which shows the distance in the structure were used. The result shows that the position in the concrete could be measured within the tolerance of ${\pm}1{\sim}4mm$ depending on the type of structure in the concrete.

Optimum Seismic Design of Reinforced Concrete Piers Considering Economy and Constructivity (내진설계시 경제성 및 시공성을 고려한 RC 교각의 최적설계)

  • 조병완;김영진;윤은이
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2000.04a
    • /
    • pp.479-484
    • /
    • 2000
  • In this study, optimal design of reinforced concrete piers under seismic load is numerically investigated. Object function is the area of the concreate-section. Design variables are the total area of reinforcement and concrete-section dimension(Circular section diameter). Constraints of the design strength of the column, longitudinal reinforcement ratio and lower and upper bounds on the design variables are imposed. The reinforcement concrete column is analysed and designed by the Ultimated Strength Design method and load combination involving dead, live, wind and seismic load is used. For numerical optimization, ADS(Garret N, Vanderplaats_ routine is used. From the result of numerical examples, the concrete-section dimension was reduced, but longitudinal reinforcement was not changed. The results show that confinement reinforcement was reduced and confinement reinforcement spacing is increased. The higher strength of reinforcement used, the more concrete-section area was reduced.

  • PDF

An Experimental Study on the Design-Concrete for Precast Concrete (문양 콘크리트의 프리캐스트화를 위한 실험적 연구)

  • Kim Jae-Eun;Gong Min Ho;Kim Kwang Ki;Cho Sang-Young;Jung Jae Young;Jung Sang-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • v.y2004m10
    • /
    • pp.11-14
    • /
    • 2004
  • The object of this study is vibrating compaction and curing method in the production process of Design concrete for precast concrete(Design-PC) product. From change of vibrating compaction time and pre-curing time. curing temperature which would be factors of product quality in Design-PC concrete production. and research of optimized steam curing condition from relations between curing condition and strength development. basic data of vibrating compaction time and concrete steam curing method for Design-PC will be presented.

  • PDF