• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.719-724
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• 2004

The ribs of deformed bars can split the cover concrete by wedging action or shear off the concrete in front of the ribs. As slip of deformed bars increases, the rib face angle is flattened by the crushed concrete wedge, which reduces the rib face angle to a smaller bearing angle. The roles of bearing angle are explored to simulate this observation. Analytical expressions to determine bond strength for splitting and pullout failure are derived, where the bearing angle is a key variable. As the bearing angle is reduced, splitting strength decreases and shearing strength increases. When splitting strength becomes larger than shearing strength, the concrete key is supposed to be sheared off and the bearing angle is reduced with decreasing the splitting strength. As bars slip, bearing angle decreases continually so that splitting bond strength is maintained to be less than shearing bond strength. The bearing angle is found to play a key role in controlling the bond failure and determination of bond strength of ribbed reinforcing steel in concrete structures.

• Earthquakes and Structures
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• v.9 no.6
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• pp.1233-1250
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• 2015

The behavior of reinforced concrete (RC) columns made from high strength materials was investigated experimentally. Six high-strength concrete specimen columns (1:4 scale), which included three with high-strength transverse reinforcing bars and three with normal-strength transverse reinforcement, were tested under double curvature bending load. The effects of yielding strength and ratio of transverse reinforcement on the cracking patterns, hysteretic response, shear strength, ductility, strength reduction, energy dissipation and strain of reinforcement were studied. The test results indicated that all specimens failed in splitting failure, and specimens with high-strength transverse reinforcement exhibited better seismic performance than those with normal-strength transverse reinforcement. It also demonstrated that the strength of high-strength lateral reinforcing bars was fully utilized at the ultimate displacements. Shear strength formula of short concrete columns, which experienced a splitting failure, was proposed based on the Chinese concrete code. To enhance the applicability of the model, it was corroborated with 47 short concrete columns selected from the literature available. The results indicated that, the proposed method can give better predictions of shear strength for short columns that experienced a splitting failure than other shear strength models of ACI 318 and Chinese concrete codes.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.205-213
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• 2007

Strength relationships are presented through experimental data from the concrete strength tests in this study. Various strength tests such as the compressive, flexural, and splitting tensile strength and the modulus of elasticity are included. An experimental work was performed to determine the various strength characteristics for various mix designs. Three different coarse aggregates such as granite, limestone, sandstone were used and included were fine aggregates such as natural sand, washed sand and crushed sand. Also included was cement amount as experimental variable. It was confirmed that each strength value with respect to curing time is to follow a typical strength development curve. With this somewhat reliable test results various strength relationships such as flexural strength-compressive strength, splitting tensile strength-compressive strength, modulus of elasticity-compressive strength, splitting tensile strength-flexural strength were analyzed through statistics. Experimental data were well fitted to the 0.5-power relationship of flexural strength and compressive strength which has been commonly accepted. The splitting tensile strength is expected to be best in the linear relationship from the flexural strength data. Finally splitting tensile strength was found to be proportional to the 0.87 power of the cylindrical compressive strength.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.173-178
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• 1993

In order to quantify the effect of transverse reinforcement on the bond splitting behavior of reinforcement monotonic loading tests of 8 slmply beams were carried out. The reinforcing details and material properties were so determined that the bond splitting failure proceded the shear and flexural failure. A bond splitting strength derived from the experimental data and it accounts for following parameters: 1) Concrete Strength 2) Transverse reinforcement ratio and shape 3) Thickness of concrete cover 4)Deformation of reinforcement

• Advances in concrete construction
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• v.10 no.1
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• pp.81-92
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• 2020

Flexural and splitting strength behavior of conventional concrete can significantly be improved by incorporating the fibers in it. A significant number of research studies have been conducted on various types of fibers and their influence on the tensile capacity of concrete. However, as an important property, tensile capacity of fiber reinforced concrete (FRC) is not modelled properly. Therefore, this paper intends to formulate a model based on experiments that show the relationship between the fiber properties such as the aspect ratio (length/diameter), fiber content, compressive strength, flexural strength and splitting strength of FRC. For the purpose of modeling, various FRC mixes only with steel fiber are adopted from the existing research papers. Automated neural network search (ANS) is then developed and used to investigate the effect of input parameters such as fiber content, aspect ratio and compressive strength to the output parameters of flexural and splitting strength of FRC. It is found that the ANS model can be used to predict the flexural and splitting strength of FRC in a sensible precision.

• Advances in concrete construction
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• v.2 no.4
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• pp.301-308
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• 2014

The present research work is on the effect of sawdust ash (SDA) on the mechanical strengths of self compacting concrete (SCC) using naphthalene sulfonate (NS) as a plasticizer. Experiments on compressive, flexural and splitting tensile strengths are conducted and the data analyzed using the Minitab 15 software. The results showed that SDA can defer the reaction of cement hydration and prolong the setting times of cement paste. This was very much pronounced on the flexural and splitting tensile strengths at 90 days of curing which are 36 % and 33 % higher than the control strengths, respectively. The study has proposed strength relations of mortar compressive strength with the flexural and splitting tensile strengths and these are, 5 and 7 times respectively. The flexural strength is 1.5 times that of the splitting tensile. Finally, linear models were developed on these relationships.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.23-29
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• 2011

In this experimental study, bond splitting strength and behavior were evaluated through pull-out tests. The tests were conducted on a GFRP rebar with roughened surface which was produced by Canadian manufacturer. The used variables in this study were rebar diameter, cover depth and compressive strength of concrete. For each variable, five specimens were made and tested to obtain good results. The bond splitting behavior was investigated from the relationship of pull-out force and slip. The experimental bond splitting strength was compared with the predicted strength obtained from the equations presented by some researchers. The results of the comparison demonstrated that the strength could be predicted well by using the Harajli et al's equation.

• Computers and Concrete
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• v.3 no.6
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• pp.389-400
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• 2006

This paper presents the investigations towards developing a better understanding on the contribution of steel fibers on the tensile strength of high-performance fiber reinforced concrete (HPFRC). An extensive experimentation was carried out with w/cm ratios ranging from 0.25 to 0.40 and fiber content ranging from zero to 1.5 percent with an aspect ratio of 80. For 32 concrete mixes, flexural and splitting tensile strengths were determined at 28 days. The influence of fiber content in terms of fiber reinforcing index on the flexural and splitting tensile strengths of HPFRC is presented. Based on the test results, mathematical models were developed using statistical methods to predict 28-day flexural and splitting tensile strengths of HPFRC for a wide range of w/cm ratios. The expressions, being developed with strength ratios and not with absolute values of strengths and are applicable to wide range of w/cm ratio and different sizes/shapes of specimens. Relationship between flexural and splitting tensile strengths has been developed using regression analysis and absolute variation of strength values obtained was within 3.85 percent. To examine the validity of the proposed model, the experimental results of previous researchers were compared with the values predicted by the model.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.4
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• pp.25-32
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• 2005

This study was performed to evaluate the strength properties of polymer concrete using recycled aggre-gate. The compressive strength, splitting tensile strength, flexural strength and pulse velocity of polymer concrete were decreased with increasing the content of recycled aggregate. At the curing age of 7days, the compressive strength was $80.5\~88.3$ MPa, the splitting tensile strength was $9.1\~10.6$ MPa, the flexural strength was $19.2\~21.5$ MPa and the pulse velocity was $3,931\~4,041$ m/s, respectively. Also, the compressive strength, splitting tensile strength, flexural strength and pulse velocity of concrete using recycled fine aggregate were higher than that of the silica sand. Therefore, these recycled aggregate polymer concretes were estimated for high strength concrete without major problem.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.206-215
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• 2017

An experimental program was carried out to investigate the mechanical properties of high-strength concrete. High-strength concrete with compressive strengths of 80 to 120 MPa was tested. Test results are presented regarding effect of water-binder ratio on compressive strength and compressive strength gain. In addition, the effect of curing methods on compressive strength, elastic modulus, splitting tensile strength, and modulus of rupture is investigated. Test results of elastic modulus, splitting tensile strength, and modulus of rupture are compared with predictions from the current design recommendations. Predictions of elastic modulus by using KCI recommendation has good agreement with test results. However, predictions of modulus of rupture by using KCI recommendation underestimate the test results. ACI 363R recommendations predict well test results of splitting tensile strength and modulus of rupture. ACI 363R recommendations for predicting splitting tensile strength and modulus of rupture can be used for high-strength concrete with compressive strengths up to 120 MPa.