2017 Volume 71 Issue 1 Pages 218-225
In order to evaluate the expansive properties of expansive concrete, uni-axial restraint test method is stipulated in JIS A 6202 and it have been used widely as the only expansive test method. But, actually, bi-axial or tri-axial restraint condition is usual in structures and multi-axial restrained test method such as using concentric double pipe have been tested and developed. Many studies have been conducted on the effects of various experimental conditions, but, in particular, researches about the effects of eccentricity of inner steel pipe against outer steel pipe are still very limited.
This paper aims at investigating expansive properties of expansive concrete under restrained by eccentric double steel pipe with different thickness of both steel pipe and CTOC（center to center）distance of double steel pipe.
The following results were obtained,
1）By expansive force of expansive concrete, circumferential tensile strains are observed on an outer steel pipe and compressive strains are occurred on an inner steel pipe.
2）Considering the effect of CTOC distance between the outer and inner steel pipe, expansive forces of concrete mainly act on the outer steel pipe at the point of maximum or minimum CTOC distance, on the other hand, at midpoint of CTOC distance, expansive forces of concrete mainly act on the inner steel pipe, in case of using a thin-walled outer steel pipe.
