• Title/Summary/Keyword: Internal curing

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Undrained shear strength and microstructural characterization of treated soft soil with recycled materials

  • Al-Bared, Mohammed A.M.;Harahap, Indra S.H.;Marto, Aminaton;Abad, Seyed Vahid Alavi Nezhad Khalil;Ali, Montasir O.A.
    • Geomechanics and Engineering
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    • v.18 no.4
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    • pp.427-437
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    • 2019
  • Waste materials are being produced in huge quantities globally, and the usual practice is to dump them into legal or illegal landfills. Recycled tiles (RT) are being used in soil stabilisation which is considered as sustainable solution to reduce the amount of waste and solve the geotechnical problems. Although the stabilisation of soil using RT improved the soil properties, it could not achieve the standard values required for construction. Thus, this study uses 20% RT together with low cement content (2%) to stabilise soft soil. Series of consolidated undrained triaxial compression tests were conducted on untreated and RT-cement treated samples. Each test was performed at 7, 14, and 28 days curing period and 50, 100, and 200 kPa confining pressures. The results revealed an improvement in the undrained shear strength parameters (cohesion and internal frication angle) of treated specimens compared to the untreated ones. The cohesion and friction angle of the treated samples were increased with the increase in curing time and confining pressure. The peak deviator stress of treated samples increases with the increment of either the effective confining pressures or the curing period. Microstructural and chemical tests were performed on both untreated and RT-cement treated samples, which included field emission scanning electron microscopic (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX). The results indicated the formation of cementation compounds such as calcium aluminium hydrate (C-A-H) within the treated samples. Consequently, the newly formed compounds were responsible for the improvement observed in the results of the triaxial tests. This research promotes the utilisation of RT to reduce the amount of cement used in soil stabilisation for cleaner planet and sustainable environment.

The case report of C.V.A. patient with M.V.H.D (C.V.A.환자(患者)의 심장판막질환(心臟瓣膜疾患)에 대한 증례보고(症例報考))

  • Kang, Min-Joo;Jung, Ji-Chun;Lee, Won-Chul
    • The Journal of Internal Korean Medicine
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    • v.14 no.1
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    • pp.43-54
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    • 1993
  • Observing after enforcing the medication and the acupuncture theraphy on the CVA patient sick with the cerebral embolus by organic pathology of the heart and whose desease was from heat symptoms caused by exessive pathogenic factors of which caused from affection due to exogeneous factors, we obtained the results as follows; 1. Serious condition could be relieved by removing acute symptoms according to the principle of the 'In emergency causes treat the acute symptoms first, when these being relieved treat it's fundament cause'. 2. The lesion could be disable for which the traditional medication theraphy through the differentiation of symptoms-complexes had removed the symptoms caused by organic pathology of heart. 3. The acupuncture stimulation through the differentiation of symptoms seemed to influence electric conduction system. Through this case, If we objectify the diagnosis and the medical treatment, the part of the curing diseases can progress more effectively.

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The Study of Literature Review on Poisoning and the Pragmatic Significance of the Processing Method of Armeniacae Amarum Semen to use in oriental medical prescription (방제활용을 위한 행인(杏仁)의 포제 및 독성의 문헌적 고찰)

  • Kim, Se-Ran;Lee, Jin-Won;Lim, So-Yeon;Kim, Jong-Dae
    • Herbal Formula Science
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    • v.19 no.2
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    • pp.151-160
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    • 2011
  • Objectives : The purpose of this study was to investigate Armeniacae Amarum Semen of poison and the Pragmatic significance of the processing method. Methods : We researched several books dealing with Armeniacae Amarum Semen of poison and the Pragmatic significance of the processing method. Results & Conclusions : Armeniacae Amarum Semen is sweet, bitter, warm and harmful in nature. It is known as moistening the lung to arrest cough, moistening the colon, to move the bowels and promoting digestion and curing dog bites. Armeniacae Amarum Semen has toxicity, decreasing toxicity of Armeniacae Amarum Semen is boiling, peeling or roasting. If Armeniacae Amarum Semen has two seeds in one apricot or has six-floral leaf, do not used for medicinal purposes.

Effects of Yukmijihwang-tang to Recover the Brain Damage of Mice (육미지황탕이 흰쥐의 뇌손상 회복에 미치는 영향)

  • Kim, Bang-Oul;Kim, Kyoung-Sun;Jeon, Hong-Yeol;Kang, Hwa-Jeong;Kim, Jeong-Sang;Hong, Seok;Kim, Yong-Jin
    • The Journal of Internal Korean Medicine
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    • v.23 no.2
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    • pp.191-201
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    • 2002
  • Objectives : This study was designed to investigate the effects of Yukmijihwang-tang on contusion of the mice induced with medicine. Methods : I observed the effects of light and electron microscopes. and examined hematological changes and VEGF-immunohistochemistry. Results : Hematology: Leukocytes were increased significantly in a control group of mice compared with the experimental group. Light microscope : A few neurons were condensed in the 7-day experimental group, but condensed remarkedly in the 3-day control group. Most glial cells were observed in the 3-day experimental group. Edema and dilatation of vessels occurred significantly in the 3-day control group, and these results occurred weakly in the 7-day experimental group. VEGF-immunohistochemistry : VEGF-immunohistochemical reactivity for the glial cells was the highest in the 3-day experimental group, and immunoreactivity for the vessels and neurons highly increased in the 7-day experimental group. Electron microscope : In the 3-day control group, protoplasmic astrocytes concerned with angiogenesis contained weakly developed rough endoplasmic reticulum. and a few of glial filaments were observed. In the 7-day experimental group, the bundles of glial filaments were found in the cytoplasmic process of astrocytes. Conclusion : medication using Yukmijihwang-tang of mice contused by medical stress is highly effective in inflamatory response, curing cell damage and angiogenesis.

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SOLUTION OF THE SUPER BESSEL WAVE EQUATION WITH INTEGRAL PARAMETER m

  • Lee, Nae-Ja;Liu, Chang-Keng
    • Bulletin of the Korean Mathematical Society
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    • v.20 no.2
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    • pp.99-103
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    • 1983
  • Internal heat generation is one of the insidious conditions affecting the quality of an industrial product after it is cast, coated, molded, forged or laminated. Frequently, the product is pressed into service before the exothermic chemical reactions in the generic material has been completed. The heat liberated from this continuing chemical reaction or the residual deformation from the rheological activities in the materials must be adequately removed or prevented, or the product may be discolored, warped, weakened or even "ignited" spontaneously. Numerous instances of premature structural failures, product-recalls, and/or system-malfunctions have been recorded in recent history. The Coulee Dam was poured with pre-chilled concrete just to negate this freakish encore. It is well-known that concrete (a non-isotropic conducting medium), for instance, takes 28 days to develop its full strength. During this period of curing it is conceivable that the processes of internal heat generation, heat conduction and heat dissipation take place simultaneously inside the medium.he medium.

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The Effect of Boshimdan(補心丹:$\breve{b}ux\bar{i}nd\bar{a}n$) on Ischemic Heart Disease (허혈성(虛血性) 심근(心筋)에 보심단(補心丹)이 미치는 영향(影響))

  • Gang, Myeong-Seok;Go, Chang-Nam;Jo, Gi-Ho;Kim, Yeong-Seok;Bae, Hyeong-Seop;Lee, Gyeong-Seop
    • The Journal of Internal Korean Medicine
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    • v.16 no.2
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    • pp.61-73
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    • 1995
  • In this study, the effects of Boshimdan, which is used in oriental medicine for the treatment of palpitation, chest discomfort, impatience, insomnia, forgetfulness ete., were tested as a part of series of experimental verification of prescriptions treatments for preventing and curing ischemic heart. The results were as follows: 1. Boshimdan did not effectively work on heart rate of the perfused rat heart. 2. Boshimdan did not effectively work on heart pressure of the perfused rat heart. 3. Boshimdan did not effectively work on flow rate of the perfused rat heart. 4. Boshimdan was not effective in activation of GOT. 5. Boshimdan was not effective in activation of GPT. 6. Boshimdan was not effective in activation of LDH. 7. Boshimdan was not effective in activation of CPK.

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Mechanical Behavior and Characteristics of Internal Temperature and Relative Humidity of Concrete at Early Age (초기재령 콘크리트의 역학적 특성 및 온·습도 거동 특성 분석)

  • Park, Cheol Woo;Lee, Bong Hak;Hong, Seung Ki
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.184-194
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    • 2011
  • This study is to analyze the internal temperature and relative humidity of concrete at early age, as well as the mechanical behavior. Three different levels of cement unit content were cosidered as an experimental variable. In order to measure internal temperature and relative humidity immediately after concrete placement, this study developed a unique measuring device, which provided reliable results. Different cement content did not significantly affected the strengths including compressive, tensile and flexural strength and after 7 days of curing, strengths did not increase noticeably. Internal temperature reached the maximum about 11 hours later the placement and decreased after removal of forms. The internal temperature varied depending on the location and the exposure condition. In addition, the internal relative humidity was more affected by the exposure condition rather than the cement content.

A Study on the Development of a Dry PFB Method with High Fire Resistance (고강도콘크리트 내화성능을 확보한 건식화 PFB 공법 개발에 관한 연구)

  • Kim, Woo-Jae;Jung, Sang-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.11a
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    • pp.49-52
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    • 2008
  • The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire-resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire-resistant boards. 1. Improved PF board was prepared by adding inorganic fiber to existing board and using aggregate with grain size of 3mm or less. Molding was done at temperature higher than that for existing PF board molding. While wet curing is used for existing PF boards, this study used dry curing in order to enhance heat insulation performance. 2. According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116℃ in 15mm, 103.8℃ in 20mm, and 94℃ in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3-hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.

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A study on color characteristics of Multi-color functional Rapid Prototypes Using laser stereolithography (광조형을 이용한 다색 기능성 시작품의 색상특성에 관한 연구)

  • 조진구;정해도;손재혁;임용관
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.824-828
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    • 2000
  • As production cycle has become more and more shorter, the demand of rapid prototyping technology has increased largely. There are many methods for rapid prototyping technology, such as SLA. SLS, FDM. INK JET, LOM and so on. Of all methods, SLA has been most widely used for fabricating precision parts. But products manufactured by this method have limitation of single color and single material. So the principal purpose of this study is to overcome the limit of single color product. If the internal structure of manufactured product is visible with multi-color characteristic, it is possible to check easily the designed model with reality. In order to give multi-color characteristic to the product, photocurable resin mixed with pigment is used in this study. First, transparency of photocurable resin without pigment is evaluated, and then color characteristic and curing characteristic of the mixture is evaluated changing mixing ratio. Through the basic experiments, it becomes possible to fabricate multi-color 3D prototype without assembly.

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An Experimental Study of Precast concrete Alters Cement Types of High-Strength Concrete (시멘트종류를 변화시킨 프리캐스트 고강도 콘크리트의 실험적 연구 - 수화열 온도특성을 중심으로 -)

  • Park, Heung-Lee;Kim, Sung-Jin;Paik, Min-Su;Lee, Seung-Hoon;Park, Byung-Keun;Jung, Sang-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2009.05b
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    • pp.119-122
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    • 2009
  • As architectures have recently become high-risers and mega-structured, stable high strength products have been ensured. Accordingly, use of precast concrete accouplement has been increased in order to facilitate air compression and rationalize construction. Since not only external heating but a1so internal temperature rise caused by the accumulation of cement hydration heat in manufacturing process, precast concrete members with large cross-section used for high-rise mega-structure's columns and beams may exhibit different temperature history compared to the precast concrete members for wall and sub-floor with relatively small cross-sections. Therefore, this study aims to elucidate the characteristics of temperature history of mass concrete members cast with high-strength concrete fur precast concrete application. In this study, large cross-sectional precast concrete mock-up, unit cement quantity, and temperature histories in manufacturing precast concrete member under different curing condition were inclusively investigated.

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