• 제목/요약/키워드: Strength Control

검색결과 4,186건 처리시간 0.03초

레디믹스트 콘크리트의 품질관리 프로그램 개발 (Computer Program for Quality Control of Ready Mixed Concrete)

  • 최재진;박원태
    • 한국산학기술학회논문지
    • /
    • 제3권1호
    • /
    • pp.20-26
    • /
    • 2002
  • 콘크리트의 품질관리에 활용하기 위하여 콘크리트의 시멘트-물비와 압축강도의 상관식을 시험을 통하여 구하였다. 그리고 콘크리트의 공기량, 슬림프 및 강도 시험결과를 데이터 베이스화 하고 X-R 관리도와 X-Rs 관리도를 작성하는 기능 그리고 사용재료에 대한 각종 시험결과를 정리할 수 있는 데이터 시트 기능을 가진 품질관리 프로그램을 개발하였다. 또한 이 프로그램 속에는 콘크리트 시험 비비기를 할 때의 배합계산 및 콘크리트 관련 용어사전 기능을 포함시켰다.

  • PDF

DLP방식의 치과용 3D프린팅 임시치아 소재의 기계적 특성 (Mechanical Properties of DLP-type Dental 3D Printing Temporary Tooth Material)

  • 정효경;이승희;정효경
    • 한국산업융합학회 논문집
    • /
    • 제24권3호
    • /
    • pp.373-376
    • /
    • 2021
  • Tested the flexural strength and maximum load of two types of dental 3 D printed temporary tooth materials of the DLP method. The average flexural strength was 206.98 MPa in the test group and 139.77 MPa in the control group. The average flexural strength of the experimental group was 67.21 MPa higher than that of the control group. In the maximum load experiment, an average of 44.16N in the experimental group and 37.31N in the control group were measured. The average value of 6.85N was higher in the experimental group, and the durability of the artificial tooth restoration was improved.

적산온도방식에 의한 고유동콘크리트의 강도관리에 관한 실험적 연구 (An experimental Study on the Strength Control of High Fluidity Concrete by Maturity)

  • 김무한;남재현;김규용;길배수;한장현
    • 콘크리트학회논문집
    • /
    • 제12권2호
    • /
    • pp.79-87
    • /
    • 2000
  • The strength development of concrete is influenced by temperature and cement type which greatly affect hydration degree of cement. There is not pertinent concrete strength management methods for estimating the in-place strength of concrete. One such method is the maturity concept. The maturity concept is based on the fact that concrete gains strength with time as a result of the cement hydration and, thus the rate of hydration, as in any chemical reaction, depends primarily on the concrete temperature during hydration. Thus, the strength of concrete is function of its time-temperature history. This goals of the present study are to investigate a relationship between strength of high-fluidity concrete and maturity that is expressed as a function of an integral of the curing period and temperature, predict strength of concrete.

80℃ 온수양생을 이용한 초고강도 콘크리트의 조기 강도 예측에 관한 연구 (A Study on the Prediction of Ultra-High Strength Concrete Using 80℃ Warm Water Method)

  • 여상길;하정수;명로언;김학영;공민호;정상진
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2012년도 추계 학술논문 발표대회
    • /
    • pp.93-94
    • /
    • 2012
  • In this study, prediction of later-age compressive strength of ultra-high strength concrete, based on the accelerated strength of concrete cured in 80℃ warm water was investigated. As a result, the nature of ultra-high strength concrete showed a rapid early strength enhancement, compressive strength using warm water method of 80℃ at 2days is same compressive at 28days using standard curing.

  • PDF

단열양생을 이용한 고강도 콘크리트 압축강도 추정에 관한 실험적 연구 (An Experimental Study on Estimation of Strength in High Strength Concrete Structure Using Simple Adiabatic Curing)

  • 조규현;김제섭;황병준;공민호;백민수;정상진
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
    • /
    • pp.450-453
    • /
    • 2004
  • The present study is a basic experiment on the estimation of the compression strength of high strength concrete, aiming at estimating the compression strength of mass test pieces of high strength concrete by giving the temperature hysteresis of the mass test pieces to managerial test pieces. Thus, this study made concrete test pieces in an optimal mix ratio for each strength level, and also created adiabatic curing tank and managerial test pieces. Then it carried out comparative analysis in relation to core strength and suggested equipment and a technique that can control the strength of high strength concrete mass more conveniently and accurately.

  • PDF

간편배합설계 방법을 이용한 고강도경량 자기충전콘크리트의 역학적 특성 (Mechanical properties of high strength lightweight self-compacting concrete using simple mixed design)

  • 최연왕;신화철;김용직;최욱;조선규
    • 한국콘크리트학회:학술대회논문집
    • /
    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
    • /
    • pp.204-207
    • /
    • 2004
  • In this paper, mechanical properties of the high strength lightweight self-compacting concrete with simple mixed design method was investigated. Experimental tests were performed as such compressive strength, splitting tensile strength, modulus of elasticity and density of high strength lightweight self-compacting concrete. The 28 days compressive strength of high strength lightweight self-compacting concrete with the LC replacement ratio of $100\%$ reduces about $31\%$ but LF replacement ratio of $100\%$ increase about $20\%$ compared that of the control concrete. The structural efficiency of high strength lightweight self-compacting concrete increase with proportional to the replacement into of LF. The relationship between the splitting tensile strength and 28 days compressive strength can be represented by the equation $f_s=0.076f_{ck}+0.5582$. The modulus of elasticity was found to be lower than that of normal weight concrete, ranging form 24 to 33 GPa.

  • PDF

폐유리로 제조된 인공경량골재를 이용한 모르타르의 물리적 성능에 대한 평가 (Performance Evaluation of Artificial Lightweight Aggregate Mortar Manufactured with Waste Glass)

  • 김성수;이정배;남바름;박광필
    • 콘크리트학회논문집
    • /
    • 제21권2호
    • /
    • pp.147-152
    • /
    • 2009
  • 본 연구는 국내에서 최초로 개발된 폐유리로 제조된 인공경량골재 (artifical lightweight aggregate: ALA)의 물리적 특성에 관한 연구를 통해 경량 모르타르 및 경량 콘크리트의 개발에 기초자료로 활용하기 위해 인공경량골재의 입도에 따른 3종류 (La, Lb, Lc)의 모르타르에 대하여 압축강도 실험, 단위질량 및 모르타르의 흡수율 실험을 실시하였다. 이상의 실험 결과, ALA의 밀도 및 단위질량은 내부의 독립기공구조로 인하여 보통골재의 50% 이하의 값을 나타냈으며, ALA를 사용한 모르타르의 흡수율시험 결과 Control 모르타르와 큰 차이가 없었다. 이는 ALA의 내부의 독립기공구조에 의한 것으로 판단된다. ALA를 사용한 모르타르의 경우 혼입률이 증가 할수록 압축강도와 휨강도는 감소하는 경향이 나타났으나, La50 모르타르를 제외한 모든 모르타르는 Control 모르타르 압축강도의 70% 이상을 나타내었다. 향후 광물질 혼화재, 물-시멘트비 의 조절에 따라 Control 모르타르와 동등한 강도가 발현 될 것이라 판단되며, 장기 내구성에 대한 검토도 함께 이루어져야 할 것으로 판단된다.

율동적 동작(Dance movement) 훈련이 노년기 여성의 생리, 심리적 변수에 미치는 영향 (Effect of Korean Traditional Dance Movement Training on Psychophysiological Variables in Korean Elderly Women)

  • 전미양;최명애
    • 대한간호학회지
    • /
    • 제26권4호
    • /
    • pp.833-852
    • /
    • 1996
  • Regular long term dance movement could be one of ways to induce improvement of psychophysiological variables, resulting in improvement of quality of life. However, there have been few studies to evaluate the effect of dance movement training on both physiological and psychological variables in the elderly. This study was focused to determine the effect of Korean traditional dance movement training on psychophysiological variables-body weight, body fat, lean body mass, muscle strength, muscle endurance, flexibility, agility, resting heart rate and blood pressure, depression and life satisfaction-in Korean elderly women. Thirty four subjects, aged between 65 and 75years who have normal cognition, sensory function, cerebellum function, cardiovascular function, participated in this study. Seventeen experimental group subjects were selected from E-elderly university in Kyung Gi province, and Seventeen control group subjects were selected from N-welfare facility in Seoul City. Seventeen experimental group subjects participated for 12weeks dance movement program. Korean traditional dance movement program was developed on the basis of Korean traditional dance and music by the author. The program consisted of approximately 50minutes of dance, 3times a week for 12weeks. During 50minutes workout, there were 15minutes of warm-up dancing, 25minutes of conditioning dance and 10minutes of cool-down dancing. The intensity for the conditioning phase was at between 60% and 65% of age-adjusted maximum heart rates. The body weight, body fat, lean body mass, muscle strength(grip strength, leg strength), muscle endurance, flexibility, agility, resting heart rate and blood pressure, depression and life satis-faction were measured prior to and following the experimental treatment. The participants in dance movement were interviewed focusing on subjective feeling following 12 week's regular dance movement. Data were analyzed with mean, standard deviation, percentage of change, X²-test, t-test, and ANCOVA test using SPSS PC/sup +/ program. Subjective feeling was categorized into cognitopsy-chological and physiological responses. Results were obtained as follows : 1) The body weight (F=15.52, p=.000), body fat (F=18.33, p=.000) and lean body mass (F=7.28, p=.011) of the experimental group were significantly lower than those of the control group following the dance movement training. 2) The leg strength (F=30.96, p=.000), muscle endurance (F=9.06, p=.005), agility(F=44.92, 000), flexibility(F=6.84, p=.014) of the experimental group were significantly higher than those of the control group following the dance movement training. There was no significant difference of grip strength(F=.43, p=.515) between experimental and control groups. 3) The heart rate(F=26.96, p=.000), systolic (F=10.40, p=.000) and diastolic(F=3.99, p=.005) blood pressure at rest of the experimental group were significantly lower than those of the control group following the dance movement training. 4) No significant difference of score of depression (F=3.49, p=.071) was observed between experimental and control groups. 5) Score of life satisfaction of experimental group was remarkably higher than that of control group following 12weeks of dance movement training (p<0.05). 6) Thematic responses about the dance movement following the training were positive. "I feel good" was the most frequent among cognitopsychological responses and "I feel lightness of body" was the most frequent among physiological responses. The results suggest that Korean traditional dance movement training can improve psychophysiological variables of Korean elderly.

  • PDF

고등학생이 인식하는 친구지지, 가족건강성과 자기통제력의 관계 (The Relationship among Peer Support, Family Strength and Self-Control in High School Students)

  • 홍승화;신효식;이선정
    • 한국가정과교육학회지
    • /
    • 제25권3호
    • /
    • pp.79-91
    • /
    • 2013
  • 본 연구는 고등학생이 인식하는 친구지지, 가족건강성과 자기통제력의 관계를 분석함으로써 자기통제력을 향상시킬 수 있는 방안을 모색하며 가정과 학교에서 고등학생을 지도하는 데 있어 기초적인 자료를 제공하고자 한다. 본 연구의 결과를 요약하면 다음과 같다. 첫째, 고등학생들의 친구지지와 가족건강성은 중간값(3.0)보다 높았고, 자기통제력 중 장기적인 만족을 추구하는 정도는 중간값보다 높고, 즉각적인 만족을 추구하는 정도는 중간값보다 낮았다. 둘째, 친구지지는 성별에 따라 유의미한 차이가 나타났고, 가족건강성은 생활수준과 부모의 학력에 따라 부분적으로 차이가 나타났다. 또한 자기통제력은 성별과 부학력에 따라 유의미한 차이가 나타났다. 셋째, 가족건강성과 자기통제력 사이에 유의한 상관이 있는 것으로 나타났고 친구지지와 자기통제력 사이에는 유의한 상관이 나타나지 않았다. 넷째, 자기통제력에 유의미한 영향을 미치는 변인들은 역할공유 및 문제해결력, 의사소통 및 가족유대, 부학력이었으며, 이 변인들은 자기통제력을 15% 설명해 주었다. 이와 같은 연구 결과를 살펴볼 때 고등학생의 자기통제력에는 가족건강성의 영향력이 크다는 것을 알 수 있다. 따라서 가정의 역할이 중요하므로 가족 간의 유대를 강화하고 긍정적인 의사소통을 하도록 가정과교육을 강화하며, 고등학생의 자기통제력을 증진시킬 수 있는 프로그램을 개발하여 제공할 필요가 있다.

  • PDF

걷기 훈련이 재택 노인의 낙상방지 체력에 미치는 영향 (Effect of Walk Training on Physical Fitness for Prevention in A home Bound Elderly)

  • 최명애;전미양;최정안
    • 대한간호학회지
    • /
    • 제30권5호
    • /
    • pp.1318-1332
    • /
    • 2000
  • The purpose of this study was to determine the effect of walk training on leg strength, flexibility, postural stability, balance and gait in home bound elderly women. Eighteen elderly women of the experimental group aged between 70 and 90 years image who have normal vision, hearing and Romberg test. They participated in the 12 week walk training. The subjects of the experimental group practiced walk training 3 times a week for during 12 weeks. During the 40 minute workout, the subjects practiced 5 minutes of warming-up exercises, 30 minutes of conditioning exercises and 10 minutes of a cool-down exercise. The intensity for the conditioning phase was determined by subject' heart rates, which ranged from 60% to 70% of age-adjusted maximum heart rates. The body composition, leg strength, flexibility, postural stability, balance and gait were measured prior to and after the experimental treatment. The body fat, lean body mass, leg strength (ankle dorsiflexor, plantarflexor, inversor and eversir, knee flexor, extensior), flexibility (range of motion of ankle dorsiflexion, plantarflexion, inversion and eversion), and postural stability of the experimental group were significantly greater than those of the control group. Duration of standing on the right foot and that of standing on the left foot of the experimental group was greater than that of the control group. Total balance scores of the experimental group were significantly higher than those of the control group. Among 13 items for balance, the scores of experimental group in balance with eyes closes, turning balance, sternal nudge, neck turning, one leg standing balance and back extension were higher than those of the control group. Total scores of gait of the experimental group were significantly higher than those of the control group following the walking training. Scores of experimental group in step height, step length and walk stance while walking among 9 items for gait were significantly higher than those of the control group. The results suggest that walk training can improve physical fitness for prevention in home bound elderly women.

  • PDF