Stress-Strain Relations of High-Strength Concrete under Triaxial Compression

This research study is to introduce and investigate an effective technique of external pre-tensioning using steel strapping (SSTT) to reduce the brittleness and enhance the ductility of high-strength concrete cylinders. Fifteen cylinders with dimension of 150 mm and 300 mm in diameter and height respectively were casted, pre-tensioned with two and four layers of steel strapping and tested to failure under uniaxial monotonic and cyclic compression. The behaviour of SSTT confined cylinders was studied through their stress-strain relationship upon the longitudinal deflection, transverse strain, mode of failure, confinement ratio, and existence of an envelope curve. It is experimentally proved that SSTT confinement do helps in controlling the brittleness problem of high-strength concrete and at the same time, enhancing both the concrete ductility and compressive strength up to 46.2 % and 112.5 % respectively. The envelope curve of uniaxial cyclic loading also coincides with the corresponding monotonic loading curve, regardless of any loading activity. The observed stress-strain relationship of confined cylinders with different confining ratios are compared with existing strength and strain models and a stress-strain prediction model, the result showed a linear relationship between the compressive strength and strain enhancement and confining ratio, with acceptable agreement between the prediction model.

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Closure to “Stress-Strain Model for High-Strength Concrete Confined by Welded Wire Fabric” by Sami W. Tabsh

Journal of Materials in Civil Engineering ◽

10.1061/(asce)0899-1561(2009)21:1(45) ◽

2009 ◽

Vol 21 (1) ◽

pp. 45-46

Author(s):

Sami W. Tabsh

Keyword(s):

High Strength Concrete ◽

High Strength ◽

Stress Strain ◽

Strength Concrete ◽

Strain Model

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Comparison of Stress-Strain Relationships of FRP and Actively Confined High-Strength Concrete: Experimental Observations

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.919-921.29 ◽

2014 ◽

Vol 919-921 ◽

pp. 29-34 ◽

Cited By ~ 1

Author(s):

Jian Chin Lim ◽

Togay Ozbakkloglu

Keyword(s):

High Strength Concrete ◽

Axial Stress ◽

Axial Strain ◽

High Strength ◽

Confining Pressure ◽

Confined Concrete ◽

Lateral Strain ◽

Stress Strain ◽

Strength Concrete ◽

Actively Confined Concrete

It is well established that lateral confinement of concrete enhances its axial strength and deformability. It is often assumed that, at a same level of confining pressure, the axial compressive stress and strain of fiber reinforced polymer (FRP)-confined concrete at a given lateral strain are the same as those in concrete actively confined concrete. To assess the validity of this assumption, an experimental program relating both types of confinement systems was conducted. 25 FRP-confined and actively confined high-strength concrete (HSC) specimens cast from a same batch of concrete were tested under axial compression. The axial stress-strain and lateral strain-axial strain curves obtained from the two different confinement systems were assessed. The results indicate that, at a given axial strain, lateral strains of actively confined and FRP-confined concretes correspond, when they are subjected to the same lateral confining pressure. However, it is observed that, at these points of intersections on axial strain-lateral strain curves, FRP-confined concrete exhibits a lower axial stress than the actively confined concrete, indicating that the aforementioned assumption is not accurate. The test results indicate that the difference in the axial stresses of FRP-confined and actively confined HSC becomes more significant with an increase in the level of confining pressure.

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