• Title/Summary/Keyword: Low replacement ratio

Search Result 219, Processing Time 0.032 seconds

Properties of the high strength and self-compacting concrete according to the replacement ratio of fly ash (플라이애쉬의 치환율에 따른 고강도 자기충전 콘크리트의 특성)

  • Kwon, Yeong-Ho;Lee, Hyun-Ho;Lee, Hwa-Jin;Ha, Jae-Dam
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.05b
    • /
    • pp.85-88
    • /
    • 2006
  • This study describes the optimum mix proportion of the high strength and self-compacting concrete placed in main structures of LNG above tank. This concrete requires high strength level about $60{\sim}80MPa$, low hydration heat, balance between workability and consistency without vibrating in the actual work. For this purpose, low heat portland cement and fly ash are selected and design factors including water-binder ratio, replacement ratio of fly ash are tested. As experimental results, low heat portland cement shows lower the confined water ratio than another cement type and the optimum replacement ratio of fly ash in order to improve properties of the binder-paste shows 10% by cement weight considering test results of the confined water ratio$({\beta}p)$. Also, flowability of the high strength and self-compacting concrete by using fly ash about $10{\sim}20%$ is improved. The replacement ratio of fly ash 10% and water-binder ratio $25{\sim}27%$ are suitable to the design strength 80MPa and cost, In case of the design strength 60MPa, the replacement ratio of fly ash and water-binder ratio show 20% and $25{\sim}30%$ separately. Based on the results of this study, the optimum mix proportions of the high strength and self-compacting concrete will be applied to the construction of LNG above tank as a new type.

  • PDF

Comparison Study on Stress Sharing Characteristics of Sand or Gravel Compaction Piles with Low Replacement Area Ratio (모래와 쇄석을 이용한 저치환율 다짐말뚝공법의 응력분담특성에 관한 비교)

  • You, Seung-Kyong;Cho, Sung-Min;Kim, Ji-Yong;Shim, Min-Bo
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2005.10a
    • /
    • pp.443-452
    • /
    • 2005
  • The compaction pile methods with low replacement area ratio used sand(SCP) or gravel(GCP) has been usually applied to improvement of soft clay deposits. In order to design accurately compaction pile method with low replacement area ratio, it is important to understand the mechanical interaction between sand piles and clays and its mechanism during consolidation process of the composition ground. In this paper, a series of numerical analyses on composition ground improved by SCP and GCP with low replacement area ratio were carried out, in order to investigate the mechanical interaction between sand piles and clays. The applicability of numerical analyses, in which and elasto-viscoplastic consolidation finite element method was applied, could be confirmed comparing with results of a series of model tests on consolidation behaviors of composition ground improved by SCP. And,through the results of the numerical analyses, each mechanical behaviors of compaction piles and clays in the composition ground during consolidation was elucidated, together with stress sharing mechanism between compaction piles and clays.

  • PDF

A Study on the Behavior of Sand Compaction Piles in Soft Ground (연약지반에 적용된 모래다짐말뚝의 거동특성에 관한 수치해석 연구)

  • Lee, Jungsang;Chung, sungrae;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
    • /
    • v.12 no.8
    • /
    • pp.33-38
    • /
    • 2011
  • Presently, domestic SCP method with low replacement ratio is required as alternative in order to overcome the profitability of the sand resource because of the deficiency phenomenon of the sand resource by the actual condition design and construction is made by SCP method with low replacement ratio more than 70% for the port construction in the safe side. Sand compaction pile(SCP) method has been mainly used to improve the properties of soft clay or loose sandy ground. In design of SCP at soft clay ground, it is very important to determine the stress concentration ratio of composite ground relevant to the area replacement ratio. In this study, 2-dimensional FEM analyses were carried out to evaluate the stress concentration ratio of composite ground depending upon the area replacement ratio. When the interpretation result replacement ratio was 30%, the stress assigned rate showed and as the replacement ratio was high, the stress assigned rate according to the sinkage showed the low stress assigned rate.

Study on Stress Sharing Mechanism Composition Ground Improved by SCP with Low Replacement Area Ratio (저치환율 SCP에 의한 복합지반의 응력분담 메커니즘에 관한 연구)

  • You, Seung-Kyong;Matsui, Tamotsu;Hong, Won-Pyo;Yoon, Gil-Lim
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2004.03b
    • /
    • pp.197-202
    • /
    • 2004
  • In order to design accurately sand compaction pile (SCP) method with low replacement area ratio, it is important to understand the mechanical interaction between sand piles and clays and its mechanism during consolidation process of the composition ground. In this paper, a series of numerical analyses on composition ground improved by SCP with low replacement area ratio were carried out, in order to investigate the mechanical interaction between sand piles and clays. The applicability of numerical analyses, in which an elasto-viscoplastic consolidation finite element method was applied, could be confirmed comparing with results of a series of model tests on consolidation behaviors of composition ground improved by SCP. And, through the results of the numerical analyses, each mechanical behaviors of sand piles and clays in the composition ground during consolidation was elucidated, together with stress sharing mechanism between sand piles and clays.

  • PDF

The Study on the Physical and Strength Properties of Lightweight Concrete by Replacement Ratio of Artificial Lightweight Aggregate (인공경량골재 혼합비율에 따른 경량 콘크리트의 물성 및 강도특성에 관한 연구)

  • Choi, Se-Jin;Kim, Do-Bin;Lee, Kyung-Su;Kim, Young-Uk
    • Journal of the Korea Institute of Building Construction
    • /
    • v.19 no.4
    • /
    • pp.313-322
    • /
    • 2019
  • This study is to compare and analyze the physical and strength properties of lightweight concrete using domestic lightweight aggregate by replacement ratio of artificial lightweight fine and coarse aggregate after considering low cement mixture and pre-wetting time. The slump, unit weight, compressive strength and split tensile strength of lightweight concrete with domestic lightweight aggregate were measured. As test results, the slump of lightweight concrete by replacement ratio of lightweight fine aggregate increased as the replacement ratio of lightweight fine aggregate increased. The unit weight of lightweight concrete using 100% of lightweight fine aggregate was about 10.4% lower than that of the lightweight concrete with natural sand. In addition, the unit weight of lightweight concrete by replacement ratio of lightweight coarse aggregate increased with the increase of the ratio of LWG10(5~10mm). The compressive strength of lightweight concrete with lightweight fine and coarse aggregate increased as the replacement ratio of lightweight fine aggregate increased. The compressive strength of lightweight concrete with natural sand and LWG10 was 30 to 31MPa regardless of the replacement ratio of the lightweight coarse aggregate after 7 days.

Experimental Study on Stress Sharing Behavior of Composition Ground Improved by Sand Compaction Piles with Low Replacement Area Ratio (저치환율 모래다짐말뚝에 의한 복합지반의 응력분담거동에 대한 실험적 연구)

  • 유승경
    • Journal of the Korean Geotechnical Society
    • /
    • v.19 no.5
    • /
    • pp.253-261
    • /
    • 2003
  • Mechanical behavior of composition pound improved by sand compaction pile (SCP) with low replacement area ratio could be more significantly affected by mechanical interaction between sand piles and clays than that of clay ground improved by SD or SCP with high replacement area ratio. It is essential to elucidate the mechanical interaction in the improved clay ground, in order to accurately estimate behavior in reducing settlement of the improved ground and increasing strength of clays. In this paper, through a series of model tests of composition ground improved by SCP with low replacement area ratio, each mechanical behaviors of sand piles and clays in the composition ground during consolidation was elucidated, together with stress sharing behavior between sand piles and clays.

Evaluation of the Low Replacement Reinforced Ground Using Laboratory Tests (실내시험을 이용한 저치환 보강지반의 평가)

  • Bae, Woo-Seok
    • Journal of the Korean Society of Safety
    • /
    • v.23 no.6
    • /
    • pp.131-137
    • /
    • 2008
  • SCP(Sand Compaction Pile) method that forms a composite ground by driving compacted sand piles into the soft ground. This method is one of the soil improvement techniques for reinforcing and strengthening soft ground deposits. This thesis describes the investigation on the behavior of soft ground reinforced with SCP by low improvement ratio. Direct shear test and consolidation test carried out to verified behavior of composite ground reinforced with SCP. Test results were discussed with reference to the amount of consolidation settlement, variation of shear resistance with area replacement ratio and effect of the stress concentration. And, laboratory model loading test carried out to verified the effect of the location and failure mode of reinforced embankment. Residual shear strength varies with the area replacement and constrict load in the low replacement ratio. Calculated stress concentration ratio overestimate than proposed valve by experimental, theoretical and analytical method. As regards the location, improving right below of the top of the slope was more effective than below of the toe of the slope. This thesis carried out to obtain fundamental information of behavior of the composit ground. Hereafter, centrifuge test that reproduce stress state of the in-situ must be necessary through the further study about pile penetration, reinforce position and construct time.

Reduction of Autogenous Shrinkage of HPFRCC Depending on Changes of ERCO Replacement Ratio and Fiber Replacement Ratio (ERCO 혼입율과 섬유혼입비 변화에 따른 HPFRCC의 자기수축저감)

  • Lee, Jea-Hyeon;Baek, Cheol;Jo, Man-Ki;Jo, Sung-Jun;Lee, Jong-Tea;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2016.05a
    • /
    • pp.30-31
    • /
    • 2016
  • As the treatments of many kinds of explosive objects increase recently, it is in the trend that explosion accidents increase. Thus, many studies on HPFRCC (High-performance Fiber-reinforced Cement Composites) whose ductility is enhanced are being conducted actively in order to minimize the damages from explosion accidents. However, HPFRCC, the self-shrinkage of HPFRCC is on the rise as a problem since it becomes ultra-high strengthened by using low W/B. Thus, in this study, it is intended to evaluate the capacity for reducing the self-shrinkage of HPFRCC depending on some changes of ERCO(Emulsified Refined Cooking Oil) replacement ratio and the fiber replacement ratio between some short steel fibers (SS) and some long organic fibers (OL). As a result, it was found that some excellent effects are exerted since the self-shrinkage was reduced a lot as the ERCO replacement ratio increases and the fiber replacement ratio of SS rather than OL increases.

  • PDF

An Experimental Study on the Effects of Crushed Stone Compaction Pile in the Sea Clay Layer (해성 점토지반의 쇄석다짐말뚝 보강 효과에 관한 실험적 연구)

  • Lee, Seung-Bong;Im, Jong-Chul;Park, Lee-Keun;Joo, In-Gon
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2005.03a
    • /
    • pp.1031-1038
    • /
    • 2005
  • Recently, due to lack of sand suppy, the cost of sand has increase. Therefore, alternative materials are needed. So, in this study the Crush Stone Compaction Pile used in America and Europe has been compared and analyzed Sand Compaction Pile used in Korea. Tests were performed at various sizes of Crush Stone and replacement ratio. Frist, it was compared and analyzed with low and high replacement ratio with the same size of crush stone. Second, it was compared and analyzed with different size of crush stone at constant replacement ratio. The result of these tests were compared with sand of the same replacement ratio. Here, the properties that were comares and analyzed are the ultimate bearing capacity and quantity of ground upheaval.

  • PDF

Stress Sharing Behaviors and its Mechanism During Consolidation Process of Composition Ground Improved by Sand Compaction Piles with Low Replacement Area Ratio (저치환율 SCP에 의한 복합지반의 압밀 과정중에 발생하는 응력분담거동과 그 메커니즘)

  • 유승경
    • Journal of the Korean Geotechnical Society
    • /
    • v.19 no.5
    • /
    • pp.301-310
    • /
    • 2003
  • In order to design accurately sand compaction pile (SCP) method with low replacement area ratio, it is important to understand the mechanical interaction between sand piles and clays and its mechanism during consolidation process of the composition ground. In this paper, a series of numerical analyses on composition ground improved by SCP with low replacement area ratio were carried out, in order to investigate the mechanical interaction between sand piles and clays. The applicability of numerical analyses, in which an elasto-viscoplastic consolidation finite element method was applied, could be confirmed comparing with results of a series of model tests on consolidation behaviors of composition ground improved by SCP. And, through the results of the numerical analyses, each mechanical behavior of sand piles and clays in the composition ground during consolidation was elucidated, together with stress sharing mechanism between sand piles and clays.