抄録
The expansion characteristics of expansive concrete are greatly dependent upon the restraint condition of concrete itself. In this study, the restrained expansive strains of main (longitudinal) and lateral reinforcing steels embeded in expansive concrete as well as the relations between them were investigated experimentally and theoretically. Authors reported previously the method of calculating the restrained strains of expansive concrete having only longitudinal reinforcement, that is, under uniaxial restraint. But under biaxial restraint, the chemical prestressing in one direction due to the restraining steel reduces the expansion in another direction. By considering the poisson's effects, the next equation was proposed.
εRX=εRx0-Kx×εRY+ν×εcey
where, εRX, εRY; restrained expansive strains under biaxial restraint in the direction of X and Y, respectively,
εRx0; restrained expansive strains under uniaxial restraint,
ν; poisson's ratio (=0.2),
εcey; elastic strain caused by chemical prestressing,
Kx; expansion reducing coefficient.
The results obtained from experiments and theoretical analysis are summarized as follows.
(1) The restraint expansive strain of main (longitudinal) reinforcement are not strongly affected by the lateral reinforcement.
(2) Chemical prestressing in the direction of main reinforcement reduces the expansion in the direction of lateral reinforcement and the expansion reducing coefficient K may be expressed as a function of lateral reinforcement ratio.
