Proposed mathematical model for stress- strain behaviour of geopolymer concrete

Bitla Srivathsav,C Vivek Kumar,N Prem Kumar,S Shrihari,S Tummala,S Kosaraju,P Bobba,S Singh

doi:10.1051/e3sconf/202130901053

Abstract

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.

Highlights

One of the most essential tasks in studying the stressstrain behaviour of Geopolymer concrete is to develop adequate analytic stress-strain models that represent the true behaviour
Empirical equations are constructed to characterise uni-axial stress-strain behaviour of conventional and Geo polymer concrete mixes of standard grade concrete after experimentally acquiring the stress-strain behaviour of conventional and Geo polymer concrete (M20)
The stress-strain behaviour of all the have been developed, both for ascending and controlled and geopolymer concrete mixes is virtually descending sections of the curves with various same, according to the observations derived from sets of constants

Summary

Introduction

One of the most essential tasks in studying the stressstrain behaviour of Geopolymer concrete is to develop adequate analytic stress-strain models that represent the true (observable) behaviour. The development of an appropriate analytic stress-strain mathematical model that can represent the real (observable) stress-strain behaviour of geo polymer concrete is completed. Boundary conditions for ascending and descending portions of stress-strain curves are, (1) At the origin the ratio of stresses and strains are zero i.e. at ( / o )= 0,(f / fo ) = 0. Equations are used to get the corresponding A, B, C constants for the ascending section and D, E, F constants for the descending portion of the analytical stress-strain curve

Theoretical Stresses

When compared to the empirical equations of