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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Computers and Concrete
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Volume & Issues
Volume 14, Issue 6 - Dec 2014
Volume 14, Issue 5 - Nov 2014
Volume 14, Issue 4 - Oct 2014
Volume 14, Issue 3 - Sep 2014
Volume 14, Issue 2 - Aug 2014
Volume 14, Issue 1 - Jul 2014
Volume 13, Issue 6 - Jun 2014
Volume 13, Issue 5 - May 2014
Volume 13, Issue 4 - Apr 2014
Volume 13, Issue 3 - Mar 2014
Volume 13, Issue 2 - Feb 2014
Volume 13, Issue 1 - Jan 2014
Selecting the target year
Web-shear capacity of prestressed hollow-core slab unit with consideration on the minimum shear reinforcement requirement
Lee, Deuck Hang ; Park, Min-Kook ; Oh, Jae-Yuel ; Kim, Kang Su ; Im, Ju-Hyeuk ; Seo, Soo-Yeon ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 211~231
DOI : 10.12989/cac.2014.14.3.211
Prestressed hollow-core slabs (HCS) are widely used for modern lightweight precast floor structures because they are cost-efficient by reducing materials, and have excellent flexural strength and stiffness by using prestressing tendons, compared to reinforced concrete (RC) floor system. According to the recently revised ACI318-08, the web-shear capacity of HCS members exceeding 315 mm in depth without the minimum shear reinforcement should be reduced by half. It is, however, difficult to provide shear reinforcement in HCS members produced by the extrusion method due to their unique concrete casting methods, and thus, their shear design is significantly affected by the minimum shear reinforcement provision in ACI318-08. In this study, a large number of shear test data on HCS members has been collected and analyzed to examine their web-shear capacity with consideration on the minimum shear reinforcement requirement in ACI318-08. The analysis results indicates that the minimum shear reinforcement requirement for deep HCS members are too severe, and that the web-shear strength equation in ACI318-08 does not provide good estimation of shear strengths for HCS members. Thus, in this paper, a rational web-shear strength equation for HCS members was derived in a simple manner, which provides a consistent margin of safety on shear strength for the HCS members up to 500 mm deep. More shear test data would be required to apply the proposed shear strength equation for the HCS members over 500 mm in depth though.
Fuzzy logic approach for estimating bond behavior of lightweight concrete
Arslan, Mehmet E. ; Durmus, Ahmet ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 233~245
DOI : 10.12989/cac.2014.14.3.233
In this paper, a rule based Mamdani type fuzzy logic model for prediction of slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes were discussed. In the model steel rebar diameters and development lengths were used as inputs. The FL model and experimental results, the coefficient of determination R2, the Root Mean Square Error were used as evaluation criteria for comparison. It was concluded that FL was practical method for predicting slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes.
Prediction of compressive strength of slag concrete using a blended cement hydration model
Wang, Xiao-Yong ; Lee, Han-Seung ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 247~262
DOI : 10.12989/cac.2014.14.3.247
Partial replacement of Portland cement by slag can reduce the energy consumption and
emission therefore is beneficial to circular economy and sustainable development. Compressive strength is the most important engineering property of concrete. This paper presents a numerical procedure to predict the development of compressive strength of slag blended concrete. This numerical procedure starts with a kinetic hydration model for cement-slag blends by considering the production of calcium hydroxide in cement hydration and its consumption in slag reactions. Reaction degrees of cement slag are obtained as accompanied results from the hydration model. Gel-space ratio of hardening slag blended concrete is determined using reaction degrees of cement and slag, mixing proportions of concrete, and volume stoichiometries of cement hydration and slag reaction. Furthermore, the development of compressive strength is evaluated through Powers` gel-space ratio theory considering the contributions of cement hydration and slag reaction. The proposed model is verified through experimental data on concrete with different water-to-binder ratios and slag substitution ratios.
Prediction of ions migration behavior in mortar under 2-D ALMT application to inhibit ASR
Liu, Chih-Chien ; Kuo, Wen-Ten ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 263~277
DOI : 10.12989/cac.2014.14.3.263
This study investigated four electric field configurations of two-dimensional accelerate lithium migration technique (ALMT), including line-to-line, plane-to-line, contour-to-line and plane-to-plane, and analyzed the ion migration behavior and efficiency. It was found that the free ion distribution diagram and voltage distribution diagram were similar, and ions migrated in the power line direction. The electrode modules were used for the mortar specimen with w/c ratio of 0.5. The effectively processed areas accounted for 14.1%, 39.0%, 49.4% and 51.4% of total area respectively on Day 28. Larger electrode area was more advantageous to ion migration. In addition, it was proved that the two-dimensional electric field could be divided into different equifield line active regions, and regarded as affected by one-dimensional electric field, and the ion migration results in various equifield line active regions were predicted by using the duration analysis method based on the theoretical model of ion migration obtained from one-dimensional test.
Effects of confinement reinforcement and concrete strength on nonlinear behaviour of RC buildings
Yon, Burak ; Calayir, Yusuf ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 279~297
DOI : 10.12989/cac.2014.14.3.279
This paper investigates the effects of confinement reinforcement and concrete strength on nonlinear behaviour of reinforced concrete buildings (RC). For numerical application, an eleven-storey and four bays reinforced concrete frame building is selected. Nonlinear incremental static (pushover) analyses of the building are performed according to various concrete strengths and whether appropriate confinement reinforcement, which defined in Turkish seismic code, exists or not at structural elements. In nonlinear analysis, distributed plastic hinge model is used. As a result of analyses, capacity curves of the frame building and moment-rotation curves at lower end sections of ground floor columns are determined. These results are compared with each other according to concrete strength and whether appropriate confinement reinforcement exists or not, respectively. According to results, it is seen that confinement reinforcement is important factor for increasing of building capacity and decreasing of rotations at structural elements.
Effect of fiber type and content on properties of high-strength fiber reinforced self-consolidating concrete
Tuan, Bui Le Anh ; Tesfamariam, Mewael Gebregirogis ; Hwang, Chao-Lung ; Chen, Chun-Tsun ; Chen, Yuan-Yuan ; Lin, Kae-Long ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 299~313
DOI : 10.12989/cac.2014.14.3.299
Effects of polypropylene (PP) fibers, steel fibers (SF) and hybrid on the properties of highstrength fiber reinforced self-consolidating concrete (HSFR-SCC) under different volume contents are investigated in this study. Comprehensive laboratory tests were conducted in order to evaluate both fresh and hardened properties of HSFR-SCC. Test results indicated that the fiber types and fiber contents greatly influenced concrete workability but it is possible to achieve self consolidating properties while adding the fiber types in concrete mixtures. Compressive strength, dynamic modulus of elasticity, and rigidity of concrete were affected by the addition as well as volume fraction of PP fibers. However, the properties of concrete were improved by the incorporation of SF. Splitting tensile and flexural strengths of concrete became increasingly less influenced by the inclusion of PP fibers and increasingly more influenced by the addition of SF. Besides, the inclusion of PP fibers resulted in the better efficiency in the improvement of toughness than SF. Furthermore, the inclusion of fibers did not have significant effect on the durability of the concrete. Results of electrical resistivity, chloride ion penetration and ultrasonic pulse velocity tests confirmed that HSFR-SCC had enough endurance against deterioration, lower chloride ion penetrability and minimum reinforcement corrosion rate.
Automated segmentation of concrete images into microstructures: A comparative study
Yazdi, Mehran ; Sarafrazi, Katayoon ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 315~325
DOI : 10.12989/cac.2014.14.3.315
Concrete is an important material in most of civil constructions. Many properties of concrete can be determined through analysis of concrete images. Image segmentation is the first step for the most of these analyses. An automated system for segmentation of concrete images into microstructures using texture analysis is proposed. The performance of five different classifiers has been evaluated and the results show that using an Artificial Neural Network classifier is the best choice for an automatic image segmentation of concrete.
Prediction of the bond strength of ribbed steel bars in concrete based on genetic programming
Golafshani, Emadaldin Mohammadi ; Rahai, Alireza ; Kebria, Seyedeh Somayeh Hosseini ;
Computers and Concrete, volume 14, issue 3, 2014, Pages 327~345
DOI : 10.12989/cac.2014.14.3.327
This paper presents the application of multi-gene genetic programming (MGP) technique for modeling the bond strength of ribbed steel bars in concrete. In this regard, the experimental data of 264 splice beam tests from different technical papers were used for training, validating and testing the model. Seven basic parameters affecting on the bond strength of steel bars were selected as input parameters. These parameters are diameter, relative rib area and yield strength of steel bar, minimum concrete cover to bar diameter ratio, splice length to bar diameter ratio, concrete compressive strength and transverse reinforcement index. The results show that the proposed MGP model can be alternative approach for predicting the bond strength of ribbed steel bars in concrete. Moreover, the performance of the developed model was compared with the building codes` empirical equations for a complete comparison. The study concludes that the proposed MGP model predicts the bond strength of ribbed steel bars better than the existing building codes` equations. Using the proposed MGP model and building codes` equations, a parametric study was also conducted to investigate the trend of the input variables on the bond strength of ribbed steel bars in concrete.