Abstract
The purpose of this study is to obtain the thermal expansion of plain concrete under multi-axial constant stress conditions. The conclusion is the following ; The thermal expansion of concrete between 20℃ and 100℃, under constant compressive stress including biaxial loading in which maximum compressive stress is below the one third of strength, can be concluded to be equal to that without external load. Within the limit of this experiment, the strain of concrete under constant compressive stress and under high temperature, can be obtained as the sum of elastic deformation caused by external forces and by the thermal expansion without external load. The thermal expansion of concrete between 20℃ and 100℃, under multi-axial constant compressive stress in which maximum compressive stress is beyond the one third strength, is smaller than free expansion. The strain of concrete can be obtained as the sum of elastic deformation, free thermal expansion and creep strain. The creep strain of concrete at any temperature can be obtained by using "Time Temperature Equivalence Principle".
