On the analysis of stress-strain curves by means of empirical equations

The aim of this study is to determine the stress-strain behavior of basalt fibred concrete experimentally. Cylinders of standard size 150 x 300 mm are cast with with and without basalt fibres and tested in uni-axial compression under strain control as per IS: 516-1999 to understand the stress-strain behavior of basalt fibred concrete. After developing empirical equations for stress-strain curves of basalt fibred concrete, theoretical values of stresses are calculated at different values of strains in concrete based on the developed empirical equations as given above and theoretical stress-strain curves are plotted. These theoretical stress-strain curves are compared with experimental stress-strain curves and found that, theoretical stress-strain curves have shown good correlation with experimental stress-strain curves for all concrete mixes.

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Proposed mathematical model for stress- strain behaviour of geopolymer concrete

E3S Web of Conferences ◽

10.1051/e3sconf/202130901053 ◽

2021 ◽

Vol 309 ◽

pp. 01053

Author(s):

Bitla Srivathsav ◽

N Prem Kumar ◽

S Shrihari ◽

C Vivek Kumar

Keyword(s):

Mathematical Model ◽

Flexural Behavior ◽

Polymer Concrete ◽

Geopolymer Concrete ◽

Empirical Equations ◽

Stress Strain ◽

Strain Behaviour ◽

Experimental Values ◽

As Stress ◽

Stress Block

In the present study, appropriate analytic stress-strain mathematical model is developed that can capture the real (observable) stress-strain behaviour of geo polymer concrete. The geo polymer concrete mixes have shown improved stress values for the same strain levels compared to that of controlled concrete mix in M20 grade. The analytical equations for the stress-strain response of conventional and geopolymer concrete mixes have been proposed in the form of y = Ax / (1+Bx+Cx2), both for ascending and descending portions of the curves with different set of values for constants. The proposed equations have shown good correlation with experimental values. The proposed empirical equations can be used as stress block in analyzing the flexural behavior of sections of controlled and geo polymer concrete. The stress-strain curves obtained in the experiment for M20 & G20 grades of controlled and geo polymer concrete exhibit a similar trend when compared to the empirical equations of modified Saenz model. So Saenz mathematical model is successfully evaluated and validated for geopolymer concrete.

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A Review of mathematical models for prediction of Stress-strain and moment –curvature behaviour in concrete

E3S Web of Conferences ◽

10.1051/e3sconf/202018401111 ◽

2020 ◽

Vol 184 ◽

pp. 01111

Author(s):

Y Shashank Babu ◽

V Srinivasa Reddy ◽

Raju S P V ◽

M V Seshagiri Rao

Keyword(s):

Mathematical Models ◽

Strain Curve ◽

Empirical Equations ◽

Stress Strain ◽

Conventional Concrete ◽

Strain Behaviour ◽

Experimental Values ◽

Good Number ◽

Made In

In this paper, a mathematical model for predicting the stress –strain and moment curvature relations in concrete is developed. A good number of empirical equations were proposed to represent stress-strain behaviour of conventional concrete. Most of the equations can be used for the ascending portion of the curve only. In 1997 Mansur et al. have adopted Carriera and Chu (1985) model, which was based on the model proposed by Popovics (1973). As such, model proposed by Mansur et al includes both ascending and descending portions of the stress-strain curve for the confined concrete with introduction of two constants for the descending portion of the curve. Several researchers proposed various empirical equations for stress-strain behaviour as briefly reported in the previous chapter. An attempt has been made in this study to develop mathematical models for concrete in unconfined state. These analytical equations can be applied to any concrete with slight modifications. These models are developed to validate the experimental values obtained.

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