• Title/Summary/Keyword: compressive testing

Search Result 507, Processing Time 0.029 seconds

The Evaluation of Non-Destructive Formulas on Compressive Strength Using the Reliability Based on Probability (확률 기반의 신뢰도를 이용한 비파괴 압축강도 추정식 평가)

  • Park, Jin-Woo;Choo, Jin-Ho;Park, Gwang-Rim;Hwang, In-Baek;Shin, Yong-Suk
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.19 no.4
    • /
    • pp.25-34
    • /
    • 2015
  • Proposed equation is used many time in calculation of concrete compressive strength using the non-destructive testing at precision safety diagnosis. Most of proposed equation is suggested in abroad and have an error to estimate concrete compressive strength in the domestic. Therefor, proposed equation is low reliability to estimate concrete compressive and it has a significant effect in reliability of precision safety diagnosis. Nevertheless, It is possible to increase the reliability through a number of experiments from this problem that occurs in some localized part. This paper is proposed assessment formula of reliability related core compressive strength to increase the reliability. It is verified that reliability of proposed assessment formula is useful by probabilistic techniques. It is compared with each graphs of concrete compressive strength of proposed equation. It has been found that the present methods are very efficient.

Assessment of compressive strength of high-performance concrete using soft computing approaches

  • Chukwuemeka Daniel;Jitendra Khatti;Kamaldeep Singh Grover
    • Computers and Concrete
    • /
    • v.33 no.1
    • /
    • pp.55-75
    • /
    • 2024
  • The present study introduces an optimum performance soft computing model for predicting the compressive strength of high-performance concrete (HPC) by comparing models based on conventional (kernel-based, covariance function-based, and tree-based), advanced machine (least square support vector machine-LSSVM and minimax probability machine regressor-MPMR), and deep (artificial neural network-ANN) learning approaches using a common database for the first time. A compressive strength database, having results of 1030 concrete samples, has been compiled from the literature and preprocessed. For the purpose of training, testing, and validation of soft computing models, 803, 101, and 101 data points have been selected arbitrarily from preprocessed data points, i.e., 1005. Thirteen performance metrics, including three new metrics, i.e., a20-index, index of agreement, and index of scatter, have been implemented for each model. The performance comparison reveals that the SVM (kernel-based), ET (tree-based), MPMR (advanced), and ANN (deep) models have achieved higher performance in predicting the compressive strength of HPC. From the overall analysis of performance, accuracy, Taylor plot, accuracy metric, regression error characteristics curve, Anderson-Darling, Wilcoxon, Uncertainty, and reliability, it has been observed that model CS4 based on the ensemble tree has been recognized as an optimum performance model with higher performance, i.e., a correlation coefficient of 0.9352, root mean square error of 5.76 MPa, and mean absolute error of 4.1069 MPa. The present study also reveals that multicollinearity affects the prediction accuracy of Gaussian process regression, decision tree, multilinear regression, and adaptive boosting regressor models, novel research in compressive strength prediction of HPC. The cosine sensitivity analysis reveals that the prediction of compressive strength of HPC is highly affected by cement content, fine aggregate, coarse aggregate, and water content.

Elimination of the effect of strain gradient from concrete compressive strength test results

  • Tabsh, Sami W.
    • Computers and Concrete
    • /
    • v.3 no.6
    • /
    • pp.375-388
    • /
    • 2006
  • Poor strength test results are sometimes not an indication of low concrete quality, but rather inferior testing quality. In a compression test, the strain distribution over the ends of the specimen is a critical factor for the test results. Non-uniform straining of a concrete specimen leads to locally different compressive stresses on the cross-section, and eventual premature breaking of the specimen. Its effect on a specimen can be quantified by comparing the compressive strength results of two specimens, one subjected to uniform strain and another to a specified strain gradient. This can be done with the help of a function that relates two parameters, the strain ratio and the test efficiency. Such a function depends on the concrete strength and cross-sectional shape of the specimen. In this study, theoretical relationships between the strain ratio and test efficiency are developed using a concrete stress-strain model. The results show that for the same strain ratio, the test efficiency is larger for normal strength concrete than for high strength concrete. Further, the effect of the strain gradient on the test result depends on the cross-sectional shape of the specimen. Implementation of the results is demonstrated with the aid of two examples.

Evaluation of Edgewise Compressive Strength of Corrugated Fiberboard with Microflute

  • Youn, Hye-Jung;Lee, Hak-Lae;Kim, Ji-Yong;Kwon, Hyun-Seung;Chin, Seong-Min
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.39 no.5
    • /
    • pp.52-57
    • /
    • 2007
  • Corrugated fiberboard is a representative packaging material because of high compressive strength and stiffness in spite of light weight. The flutes of corrugated fiberboard are various depending on the height and the number per unit length of flute. The corrugated fiberboard with microflute like E, F or G with low height less than 1.5 mm has developed. Because it has some advantages including higher stiffness and lower requirement of fiber than carton board, it has a possibility to replace folding box board. Its consumption has been increased with the various applications like graphic packaging. As microflute has the different geometry from other conventional flutes, it can show the different behavior in testing and it may require a new testing method. In this study, we evaluated the edgewise compressive strength of the corrugated fiberboard with microflute according to ISO and other standard test methods. And the effect of specimen shape and platen compression rate was examined. From this study, we found that ISO methods was suitable and reasonable methods for corrugated fiberboard with microflute.

Estimation of Long-term Aging Compressive Strength Through Non-Destructive Testing of Concrete Structure Using Mineral Admixtures (혼화재를 사용한 콘크리트 구조체의 비파괴 시험에 의한 장기재령 압축강도 추정)

  • Kim, Jeong-Sup;Shin, Yong-Seok;Lee, Chang-Hyun;Lee, Seung-Jung;Kim, Kwang-Seok
    • Journal of the Korea Institute of Building Construction
    • /
    • v.11 no.5
    • /
    • pp.426-434
    • /
    • 2011
  • Recently, the use of mineral admixtures in concrete has been studied in many laboratories, and been applied in the field. But the non-destructive testing equation proposed in Japan for normal strength concrete has been used to determine compressive strength, because there has been a lack of systematic research on the compressive strength of concrete using mineral admixtures. For this reason, it is essential to suggest a non-destructive testing equation to estimate the compressive strength of concrete using mineral admixtures. Therefore, this study made a cylindrical specimen and core tube specimen of concrete using a mineral admixture, and suggested a strength estimation of long-term age (4 years) through non-destructive and destructive tests. The results of the research are as follows. Comparing error rates between conventional suggested equations and this estimated equation shows some differences by age, but the error rate of this study was reduced to 0.3 %~115.0 % compared to conventional equations by re-bound hammering, 0.2 %~22.8 % by the ultrasound velocity method and 0.5 %~102.3 % by complex method. Accordingly, it is judged to be suitable for assessing the compressive strength of concretes using mineral admixtures.

A Study of Compressive Strength of Two Resins on the Cavity Forms (광중합 복합레진의 압축강도에 대한 실험적 연구)

  • Park, Kyung-Hun;Lee, Chan-Young;Lee, Sung-Jong;Park, Dong-Su;Lee, Chung-Suck
    • Restorative Dentistry and Endodontics
    • /
    • v.12 no.2
    • /
    • pp.83-90
    • /
    • 1987
  • Composite resins has been widely used in dental clinics because of esthetic restoration. The aim of this study was to assess the effects of the cavity designs on the compressive stress of resin restoration. So, the author made the standardized specimen of four types (Type of speciemen are width 1.5mm, depth 2mm, width 1.5mm, depth 3mm, width 2mm, depth 2mm, width 2mm, depth 3mm). The compressive strength was measured by universal testing machine (Tong Kwang Co.) The results indicating following; 1. There was a statistic significance of compressive strength between four cavity forms. 2. There was no difference of significance of compressive strength between two resins. 3. There was a significance of compressive strength between depth 3mm width 1.5mm and depth 3mm width 2mm.

  • PDF

A Study on Dynamic Material Properties of Functional High Explosive Formulation Simulant Subjected to Dynamic Loading (동적하중을 받는 기능성 고폭화약조성 시뮬런트 재료물성 연구)

  • Park, Jungsu;Yeom, Kee Sun;Park, Chunghee;Jeong, Sehwan;Lee, Keundeuck;Huh, Hoon
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.16 no.6
    • /
    • pp.857-866
    • /
    • 2013
  • This paper is concerned with the material properties of functional high explosive(FHX) simulant at various strain rates ranging from $10^{-4}/sec$ to $10^1/sec$. Material properties of FHX at high strain rates are important in prediction of deformation modes of FHX in a warhead which undergoes dynamic loading. Inert FHX stimulant which has analogous mechanical properties with FHX was utilized for material tests due to safety issues. Uniaxial tensile tests at quasi-static strain rates ranging from $10^{-4}/sec$ to $10^{-2}/sec$ and intermediate strain rates ranging from $10^{-1}/sec$ to $10^1/sec$ were conducted with JANNAF specimen using a tensile testing machine, INTRON 5583, and developed high speed material testing machine, respectively. Uniaxial compressive tests at quasi-static strain rates and intermediate strain rates were conducted with cylindrical specimen using a dynamic materials testing machine, INSTRON 8801. And cyclic compressive loading tests were performed with various strain rates and strains. Deformation behaviors were investigated using captured images obtained from a high-speed camera.

Inspection of Underground Slurry Wall for LNG Storage Tank (LNG 저장 탱크 지중연속벽 품질시험)

  • Kim, Young-H.;Jo, Churl-Hyun;Lim, Seong-Jin
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.23 no.2
    • /
    • pp.107-115
    • /
    • 2003
  • Nondestructive testing was carried out in order to evaluate the structural integrity and construction quality of the slurry wall of the underground LNG storage tank. 9 test points were selected, and the wall thickness, rebar spacing, and compressive strength of the slurry wall were evaluated by stress wave impact-resonance method, GPR, sonic velocity, and rebound testing, respectively. As results, the wall thickness, rebar sparing and estimated compressive strength satisfy the design criteria.