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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Concrete Institute
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Journal DOI :
Korea Concrete Institute
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Volume & Issues
Volume 14, Issue 6 - Dec 2002
Volume 14, Issue 5 - Oct 2002
Volume 14, Issue 4 - Aug 2002
Volume 14, Issue 3 - Jun 2002
Volume 14, Issue 2 - Apr 2002
Volume 14, Issue 1 - Feb 2002
Selecting the target year
Relationship between Crack Characteristics and Damage State of Strengthened Beam
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 805~812
DOI : 10.4334/JKCI.2002.14.6.805
The number of old concrete structure which needs to be strengthened has been increased. The repair and strengthening methods have to be determined based on the current status of the structure. Consequently the estimation method for the damage status of the structure has been desperately needed, but no studies have been tried to use the crack and deflection characteristics to estimate the damage status. In this study, the crack characteristics depending on load level were measured and analysed. The crack characteristics observed from 11 samples were compared with damage status, and load level, The crack characteristics examined in this study include crack number, crack length, crack range, crack interval, maximum crack length, crack area, and average crack length. The deflections were normalized based on yield deflection, and the relationship between the relative deflection and the standardized crack characteristics were compared. Among the crack characteristics, crack interval, crack area, crack range, and maximum crack length, have been showed a close relationship to the relative deflection. Therefore, if such crack characteristics are evaluated, the maximum load applied to the structure is believed to be estimated. if additional parameters such as size of specimen, strength of concrete and steel, and steel ratio are studied, the damage status of structure can be estimated more accurately.
Determination of Degree of Hydration, Temperature and Moisture Distributions in Early-age Concrete
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 813~822
DOI : 10.4334/JKCI.2002.14.6.813
The purpose of the present study is first to refine the mathematical material models for moisture and temperature distributions in early-age concrete and then to incorporate those models into finite element procedure. The three dimensional finite element program developed in the present study can determine the degree of hydration, temperature and moisture distribution in hardening concrete. It is assumed that temperature and humidity fields are fully uncoupled and only the degree of hydration is coupled with two state variables. Mathematical formulation of degree of hydration Is based on the combination of three rate functions of reaction. The effect of moisture condition as well as temperature on the rate of reaction is considered in the degree of hydration model. In moisture transfer, diffusion coefficient is strongly dependent on the moisture content in pore system. Many existing models describe this phenomenon according to the composition of mixture, especially water to cement ratio, but do not consider the age dependency. Microstructure is changing with the hydration and thus transport coefficients at early ages are significantly higher because the pore structure in the cement matrix is more open. The moisture capacity and sink are derived from age-dependent desorption isotherm. Prediction of a moisture sink due to the hydration process, i.e. self-desiccation, is related to autogenous shrinkage, which may cause early-age cracking in high strength and high performance concrete. The realistic models and finite element program developed in this study provide fairly good results on the temperature and moisture distribution for early-age concrete and correlate very well with actual test data.
Load Transfer Mechanism of the Hybrid Beam-Column Connection System with Structural Tees
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 823~829
DOI : 10.4334/JKCI.2002.14.6.823
The composite frame system with reinforced concrete column and steel beam has some advantages in the structural efficiency by complementing the shortcomings between the two systems. The system, however has also a lot of problems in practical design and construction process due to the material dissimilarities. Considering these circumstances, this research is aimed at the development of the composite structural system which enables the steel beams to be connected to the R/C columns with higher structural safety and economy. Basically the proposed connection system is composed of four split tees, structural angles reinforced by stiffener, high strength steel rods, connecting plates and shear plates. The structural tests have been carried out to verify the moment transfer mechanism from beam flange to steel rods or connecting plates through the angle reinforced by siffener. The four prototype specimens have been tested until the flange of beam reached the plastic states. From the tests, no distinct material dissimilarities between concrete and steel have been detected and the stress transfer through wide flange beam - structural angle - high strength steel rod or connecting plate is very favorable.
Estimation of Strength for Flexural Members in Reinforced Concrete after High Temperature
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 830~842
DOI : 10.4334/JKCI.2002.14.6.830
The purpose of this study is to investigate the flexural strength for reinforced concrete beam members after high temperature. In order to investigate the strength of flexural members, we tested twelve reinforced concrete beam members with three reinforcement ratios (
min) and four heating conditions (non-heating, 40
-2hr/4hr and 80
-4 hr). The experimental results show that failure mode, load-displacement relationship, initial stiffness, moment-curvature relationship and moment-strain relationship are affected on reinforcement ratios and heating conditions. And we analyzed reinforced concrete beam members varying heating conditions with proposed sectional analytical method. The results of this study can be summarized as follows; (1) The specimens showed various failure modes following to the reinforcement ratios and heating conditions. At the same heating conditions, the higher reinforcement ratio, the lower the resistance load and initial stiffness of beam members. And the higher temperature, the higher strain at the same moment. (2) The values which are compared with the nominal strength and the experimental maximum load are 0.85~l.05 at 40
and 0.44~0.64 at 80
. (3) After comparing analytical value with experimental result about maximum moment of members, its average (experimental value / analytical value) shows 0.95 and we proved trustability about proposed analytical method. (4) We proposed flexural strength equation of various heating conditions for reinforced concrete beam members.
Analysis of the Linear Transformation of Prestressing Tendon Using Equivalent toad Method
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 843~850
DOI : 10.4334/JKCI.2002.14.6.843
Linear transformation theory has been effectively used in the design and analysis of prestressed concrete structures. The underlying assumptions of the theory, which were often overlooked, are investigated in the respect of equivalent load method. As a result, it is found that the same equivalent loading system is produced for all the cases of the linear transformation by the assumptions of the conventional equivalent load method. On the other hand, equivalent loading systems in a strict and accurate sense do not satisfy the classical theories of the linear transformation. Also, it is shown that a little different equivalent loading system from the conventional one is obtained for each linear transformation according to the proposed equivalent load method that is derived from the self-equilibrium property of the tendon-induced forces. Therefore, it can be concluded that the linear transformation theory is valid only when referring to the conventional approximate equivalent load method. The discussions are further extended to the eccentrically located circumferential tendon in the wall of containment structures, where the problem of eccentricity is analyzed also from the view point of the linear transformation.
Cracking Behavior of Reinforced Concrete Structures due th Reinforcing Steel Corrosion
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 851~863
DOI : 10.4334/JKCI.2002.14.6.851
Corrosion products of reinforcement in concrete induce pressure to the adjacent concrete due to the expansion of steel. This expansion causes tensile stresses around the reinforcing bar and eventually induces cracking through the concrete cover The cracking of concrete cover will adversely affect the safety as well as the service life of concrete structures. The purpose of the this study is to examine the critical corrosion amount which causes the cracking of concrete cover. To this end, a comprehensive experimental and theoretical study has been conducted. Major test variables include concrete strength and cover thickness. The strains at the surface of concrete cover have been measured according to the amount of steel corrosion. The corrosion products which penetrate into the pores and cracks around the steel bar have been considered in the calculation of expansive pressure due to steel corrosion. The present study indicates that the critical amount of corrosion, which causes the initiation of cracking, increases with an increase of compressive strength. A realistic relation between the expansive pressure and average strain of corrosion product layer in the corrosion region has been derived and the representative stiffness of corrosion layer was determined. A concept of pressure-free strain of corrosion product layer was introduced to explain the relation between the expansive pressure and corrosion strain. The proposed theory agrees well with experimental data and may be a good base for the realistic durability design of concrete structures.
Strength and Moment-Curvature Relationship of HCFT Columns under Eccentric Load
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 864~873
DOI : 10.4334/JKCI.2002.14.6.864
Recently, CFT Column has reported a lot of study result, because a CFT column has certain superior structural properties as well as good productivity, execution efficiency, and improved rigidity over existing column. However, CFT column still has problems clearing the capacity evaluation between its steel tube member and high-strength concrete materials. Also, high-strength concrete filled steel square tube column(HCFT) examined numerical value explanatorily about transformation performance(M-ø) of when short-column receives equal flexure-moment from axial stress on research for concrete. hnd, with basis assumption, executed development of analysis program of moment-curvature relation for analytic analysis of transformation performance of HCFT section that get by an experiment. This study investigated to properties of structural(capacity, curvature), through a series of experiments for HCFT with key parameters, such as strength of concrete(600kgf/
), D/t ratio, slenderness ratio(λ) and concrete kinds under eccentric load. And, I executed comparative analysis with AISC-LRFD, AIJ and Takanori Sato etc. and experiment result that is capacity design formula.
Shear Behavior of High-Strength Concrete Deep Beams and Comparisons with ACI Shear Design Provisions
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 874~882
DOI : 10.4334/JKCI.2002.14.6.874
Currently, deep beams are designed according to ACT 318-99 equations derived from experimental data for slender beams with normal-strength concrete. In addition, there is relatively limited information on high-strength concrete deep beams with shear reinforcement. The purpose of this experimental study is to investigate the shear behavior of high-strength concrete deep beams and to grasp the conservatism of ACI shear design provisions. Experimental results on the shear behavior of 22 deep beams under two equal symmetrically placed point loads are reported. compressive strength of concrete cylinder was 800kgf/
, and main variables were vertical and horizontal shear reinforcement and shear span-to-overall depth ratio (а/h). Test results showed that for high-strength concrete deep beams with shear span-to-overall depth ratio exceeding 0.75, the vertical shear reinforcement more effectively resisted the shear load than horizontal shear reinforcement. In high-strength concrete deep beams, ACI shear design provisions tended to underestimate the effect of strut-tie action and vertical shear reinforcement and overestimate the ones of horizontal shear reinforcement. Based on the experimental results of high-strength concrete deep beams and shear friction theory, this study modified the equations on the shear capacity specified by the ACI provisions.
Influence of Reinforcements on the Chloride Diffusion Analysis of Concrete Structures
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 883~891
DOI : 10.4334/JKCI.2002.14.6.883
The chloride penetration in concrete structures is influenced by many factors such as types of cement and admixture proportion. Therefore, the effects of these factors on chloride diffusion must be correctly considered. The conventional diffusion analysis also neglected the existence of reinforcing bar in concrete structures. The purpose of the present paper is therefore to investigate the effect of reinforcing bar on the chloride diffusion in concrete structures. For this purpose, a comprehensive finite element analyses have been conducted to obtain chloride penetration profile. The results indicate that the chlorides are accumulated in front of a reinforcing bar and that the accumulation is much larger for the case of large diameter bars. The higher accumulation of chloride at bar location causes much faster corrosion of reinforcing steel. It can be concluded from the present study that the effects of reinforcing bars must be considered in chloride diffusion analysis for more realistic prediction of durable life of concrete structures.
Model for fiber Cross-Sectional Analysis of FRP Concrete Members Based on the Constitutive Law in Multi-Axial Stress States
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 892~899
DOI : 10.4334/JKCI.2002.14.6.892
Among the methods for enhancement of load-carrying capacity on flexural concrete member, recently, a concept is being investigated which replaces the steel in a conventional reinforced concrete member with a fiber reinforced polymer(FRP) shell. This study focuses on modeling of the structural behavior of concrete surrounded with FRP shells in flexural bending members. A numerical model of fiber cross-sectional analysis is proposed to predict the stress and deformation state of the FRP shell and concrete. The stress-strain relationship of concrete confined by a FRP shell is formulated to be based on the constitutive law of concrete in multi-axial compressive stress state, in assuming that the compression response is dependent on the radial expansion of the concrete. To describe the FRP shell behavior, equivalent orthotropic properties of in-plane behavior from classical lamination theory are used. The present model is validated to compare with the experiments of 4-point bending tests of FRP shell concrete beam, and has well predicted the moment-curvature relationships of the members, axial and hoop strains in the section, and the enhancement of confinement effect in concrete surrounded by FRP shell.
Realistic Prediction of Post-Cracking Behaviour in Synthetic Fiber Reinforced Concrete Beams
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 900~909
DOI : 10.4334/JKCI.2002.14.6.900
Fibers play a role to increase the tensile strength and cracking resistance of concrete structures. The post cracking behavior must be clarified to predict cracking resistance of fiber reinforced concrete. The purpose of this study is to develop a realistic analysis method for the post cracking behavior of synthetic fiber reinforced concrete members. For this purpose, the cracked section is assumed to behave as a rigid body and the pullout behavior of single fiber is employed. A probabilistic approach is used to calculate effective number of fibers across crack faces. The existing theory is compared with test data and shows good agreement. The proposed theory can be efficiently used to describe the load-deflection behavior, moment-curvature relation, load-crack width relation of synthetic fiber reinforced concrete beams.
Shear Behavior Prediction of Reinforced Concrete Beams by Transformation Angle Truss Model Considered Bending Moment Effect
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 910~921
DOI : 10.4334/JKCI.2002.14.6.910
For the prediction of shear behavior of reinforced concrete beams, this paper proposed Transformation Angle Truss Model (TATM) considered bending moment effect. Shear stress-strain relationship obtained from the TATM was agreed well with test results conducted by this study Further, shear strength obtained from the TATM was compared to the experimentally observed results of 170 reinforced concrete beams which had various shear span ratios shapes of support and shapes of cross section. The shear strength of reinforced concrete beams obtained from test was better predicted by the TATM with 0.96 in average and 11.9％ in coefficient of variation than by other truss models. And the ratio of experimental results to theoretical results obtained from the TATM was almost constant regardless of the η and a/d.
Structural Behavior on the Externally Strengthened Bridge Deck with Glass Fiber Reinforced Polymer
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 922~933
DOI : 10.4334/JKCI.2002.14.6.922
Since the deterioration of concrete bridge decks affect durability, safety, and function, structural rehabilitation of damaged concrete deck that was strengthened with Fiber Reinforced Polymer(FRP) is increasing the latest. But recent studies on the strengthened structures are focused on the static behavior, however only a few studies on the fatigue behavior are performed. In this study, static and fatigue behavior of strengthened deck were peformed on 11 deck specimens strengthened with sheet typed Glass Fiber Reinforced Polymer(GFRP) that were reinforced by two different strengthening methods for the static test. A amount of strengthening material in the each direction such as transverse and longitudinal was adopted experimental variables for the static test and also the stress level of the static maximum load are adopted for the fatigue test. By the results of the experimental study, with respect to the strengthened decks, the resistance effect of crack propagation and effect of stress distribution are improved. In addition, the rate of variation of compliance decreased.
Size Effect on Flexural Compressive Strength of Reinforced Concrete Beams
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 934~941
DOI : 10.4334/JKCI.2002.14.6.934
It is important to consider the effect of member size when estimating the ultimate strength of a concrete flexural member because the strength always decreases with an increase of member size. In this study, the size effect of a reinforced concrete (RC) beam was experimentally investigated. For this purpose, a series of beam specimens subjected to four-point loading were tested. More specifically, three different effective depth (d
15, 30, and 60 cm) reinforced concrete beams were tested to investigate the size effect. The shear-span to depth ratio (a/d=3) and thickness (20 cm) of the specimens were kept constant where the size effect in out-of-plane direction is not considered. The test results are curve fitted using least square method (LSM) to obtain parameters for the modified size effect law (MSEL). The analysis results show that the flexural compressive strength and the ultimate strain decrease as the specimen size increases. In the future study, since
value suggested by design code and ultimate strain change with specimen size variation, a more detailed analysis should be performed. Finally, parameters for MSEL are also suggested.
Strength Properties of Mortar Mixed with Accelerator for Freeze Protection in Constant and Variable Temperature Condition
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 942~948
DOI : 10.4334/JKCI.2002.14.6.942
When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and the strength development may be delayed. One of the solution methods to resolve these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerator for freeze protection. In this study we Investigate the effect on the strength development of cement mortar using accelerator for freeze protection with the variable curing condition. As the result of this study, the mortar using accelerator for freeze protection show continuously the strength development in curing condition of -5
. And the compressive strength under variable temperature condition was higher than constant temperature condition in same maturity.
Numerical Study on Interior Flat Plate-Column Connections Subjected to Unbalanced Moment
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 949~960
DOI : 10.4334/JKCI.2002.14.6.949
Flat plate structures under lateral load are susceptible to punching shear failure of the slab-column connection. To prevent such brittle failure, strength and ductility of the connection should be ensured. However, due to complexity in the behavior and difficulty in simulating the actual load and boundary conditions of the flat plate system, it is not easy to obtain reliable data regarding to the strength and ductility from the previous experimental studies. In the present study, a numerical study was performed for interior connections of continuous flat plate. For the purpose, a computer program for nonlinear FE analyses was developed, and the validity was verified by comparisons with the existing experimental results. Through the parametric studies, the variations of bending moment, shear, and torsional moment around the connection were investigated. Based on the findings of the numerical studies, the aspects which need to be improved in current design methods were discussed. The results of the present study will be used for developing a design method for the flat plate-column connection in the companion paper.
Strength of Interior Plat Plate-Column Connections Subjected to Unbalanced Moment
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 961~972
DOI : 10.4334/JKCI.2002.14.6.961
Flat plate structures under lateral load are susceptible to the brittle shear failure of plate-column connection. To prevent such brittle failure, strength and ductility of the connection should be ensured. However, according to previous studies, current design methods do not accurately estimate the strength of plate-column connection. In the present study, parametric study using nonlinear finite element analysis was performed for interior connections. Based on the numerical results, a design method for the connection was developed. At the critical sections around the connection coexist flexural moment and shear developed by lateral and gravity loads, and maximum allowable eccentric shear stresses were proposed based on the interactions between the flexural moment and shear, The proposed method can precisely predict the strength of the connection, compared with the current design provisions. The predictability of the proposed method was verified by the comparisons with existing experiments and nonlinear numerical analyses.
Setting Assessment of Hogh Strength Concrete Using the Ultrasonic Pulse Velocity Monitoring
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 973~981
DOI : 10.4334/JKCI.2002.14.6.973
Recently, the use of high strength concrete (HSC) has increased dramatically md however, few studies have been conducted on the early-age properties of HSC such as setting. The penetration resistance test (specified by KS F 2436) that is the standard test method for determining initial and final setting times of concrete, may not be appropriate for HSC because of the high viscosity of the mortar mixture. To address this issue, an ultrasonic pulse velocity (UPV) monitoring system was used to investigate the setting behavior of mortar and concrete. The experimental study was carried out to measure the UPV's of mortars and concretes having various water/binder ratios (W/B) and various fly ash replacement levels, during the first 24 hours of testing. Test results showed that the UPV in concrete was developed faster than that of mortar with the same W/B, and that of ordinary concrete was greater than that of fly ash concrete. Typical values of UPV were suggested that correspond to the initial and final setting times, based on following criteria: (1) the penetration resistance method; (2) the instant when the UPV begins to develop; and (3) the instant when the UPV development rate is maximum. The method and UPV monitoring device used in this study is promising for the setting assessment of concrete, particularly for HSC.
Evaluation of the Shear Strength Component by Circular Transverse Reinforcement in Reinforced Concrete Columns
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 982~988
DOI : 10.4334/JKCI.2002.14.6.982
Current design equations for shear strength of reinforced concrete columns generally overestimate the shear strength contribution by the circular transverse reinforcement. This is due to the simplification of the discrete distribution of the reinforcement to the continuous one and the imprudent application of the classical truss model to the circular section, which is different in shear-resisting mechanism from the rectangular section. This study presents a rational model for the prediction of shear strength contribution by the circular transverse reinforcement considering the starting location of a diagonal crack, the number of transverse reinforcing bars crossing the main crack and the geometrical strength component of the transverse resistance. It was found that, for lower amount transverse reinforcement, the crack starting point and the number of crack crossing bars greatly influence the shear-resisting capacity. Proposed model leads to a reliable design equation which is derived using a linear regression method and is in good agreement with the lower bound of exact strength curve.
Equations for Estimating Energy Dissipation Capacity of Flexure-Dominated RC Members
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 989~1000
DOI : 10.4334/JKCI.2002.14.6.989
As advanced earthquake design methods using nonlinear static analysis are developed, it is required to estimate precisely the cyclic behavior of reinforced concrete members that is characterized by strength, deformability, and energy dissipation. In a recent study, a simplified method which can estimate accurately the energy dissipation capacity of flexure-dominated RC members subjected to repeated cyclic load was developed. Based on the previously developed method, in the present study, simple equations that can be used for calculating the energy dissipation capacity were derived and verified by the comparison with experimental results. Through parametric study using the proposed equations, effects of axial load, reinforcement ratio, rebar arrangement, md ductility on the dissipated energy were investigated. The proposed equations can accurately estimate the energy dissipation capacity compared with the existing empirical equations, and therefore they will be useful for the nonlinear static analysis/design methods.
Confinement Range of Transverse Reinforcements for T-shaped Reinforced Concrete Walls
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 1001~1009
DOI : 10.4334/JKCI.2002.14.6.1001
The objective of this study is to determine the range of confinement (or the transverse reinforcement of the reinforced concrete structural walls with the T-shaped cross section subjected to cyclic lateral loads. The range of confinement for transverse reinforcement is related to the location of neutral axis and determined by the magnitude and distribution of compressive strain. The compressive strain depends on the ratio of wall cross sectional area to the floor-plan area, the aspect ratio, configuration, the axial load, and the reinforcement ratios. By affection of flange, the neutral axis appears different depending on positive and negative forces and because of this reason, when web and flange are subjected to compressive stress, the range of confinement for the transverse reinforcement of T-shaped walls would shows different result. Therefore this experimental research focused on the structural characteristics of T-shaped walls and suggested the neutral axis depth through comparing the results of this study with sectional analysis.
Prediction of the Torsional Strength of Reinforced Concrete Beams Subjected to Pure Torsion
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 1010~1021
DOI : 10.4334/JKCI.2002.14.6.1010
The current ACI design code does not take into account the contribution of concrete for the torsional moment of reinforced concrete(RC) beams subjected to pure torsion. This code is not capable of evaluating the inter-effects between concrete and torsional reinforcement on the torsional resistance of the RC beams. Some test results indicated that the current ACI code was not successful in predicting the observed torsional moment of the RC beams with reasonable accuracy. The research reported in this paper provides an evaluation equation to predict the torsional moment of the RC beams subjected to pure torsion. The proposed equation is derived from the equilibrium as well as compatibility equations of the truss model for the cracked RC beams. Comparisons between the observed and calculated torsional moments of the 66 tested beams, showed reasonable agreement.
Integrity Assessment Models for Bridge Structures Using Fuzzy Decision-Making
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 1022~1031
DOI : 10.4334/JKCI.2002.14.6.1022
This paper presents efficient models for bridge structures using CART-ANFIS (classification and regression tree-adaptive neuro fuzzy inference system). A fuzzy decision tree partitions the input space of a data set into mutually exclusive regions, each region is assigned a label, a value, or an action to characterize its data points. Fuzzy decision trees used for classification problems are often called fuzzy classification trees, and each terminal node contains a label that indicates the predicted class of a given feature vector. In the same vein, decision trees used for regression problems are often called fuzzy regression trees, and the terminal node labels may be constants or equations that specify the predicted output value of a given input vector. Note that CART can select relevant inputs and do tree partitioning of the input space, while ANFIS refines the regression and makes it continuous and smooth everywhere. Thus it can be seen that CART and ANFIS are complementary and their combination constitutes a solid approach to fuzzy modeling.
Mechanical Properties of Steel Fiber Reinforced Concrete Using Waste Glass
Journal of the Korea Concrete Institute, volume 14, issue 6, 2002, Pages 1032~1039
DOI : 10.4334/JKCI.2002.14.6.1032
Since recycling waste glass as a material for concrete has a great advantage environmentally and economically, the US, Japan and other countries have started recycling waste glass widely and accumulating the technology of manufacturing equipment and its construction. However, there is no practical data on the mechanical property of concrete using waste glass. In this study, the mechanical property of the steel fiber reinforced concrete using waste glass was analyzed in terms of waste glass content(20vo1. ％, 40vo1. ％ as a part of fine aggregate) and steel fiber content(0.5~ 1.5vol.％). The results of this study are as follows : The workability of the concrete including steel fiber and waste glass decreases, as the inclusion rate of waste glass and steel fiber increases. The tensile strength, flexural strength and flexural toughness of the concrete including waste glass increase considerably, as the inclusion rate of steel fiber increases. From the results, the appropriate inclusion rate of steel fiber and waste glass is thought to be 1.0vol. % and 20vo1. ％, respectively.