Bifurcation in compressive behavior of concrete

The fundamental mechanism of the statistical variation of the compressive behavior of cylindrical concrete specimens is explained through a synthesis and a reconstruction of the bifurcation theory. Initial imperfections of the specimens, which denote the deviation of various kinds of physical properties among them, are employed to explain such statistical variation. A series of compression tests on cylindrical concrete specimens are conducted to construct a statistical data bank of compressive stress versus strain curves. An imperfection sensitivity law is employed to describe the variation in these curves, and hence to identify the existence of bifurcation that triggers the softening of the curves. The curves, in addition, are simulated well by means of the so-called bifurcation equation. The theory of the stochasticity of initial imperfections is employed to explain the probabilistic variation of the maximum axial stresses. The predominant role of bifurcation im the compressive behavior of concrete has thus been demonstrated.