To provide a mortar and a concrete which enables a large volume consumption of recycled fine powder as an area of application of liquified soil, brings about an increased recycle ratio of demolished concrete blocks and secures a sufficient strength level for a building foundation ground material.

The concrete for the building foundation ground material is a mixture of (B) recycled fine powder by-produced in producing recycled aggregate from demolished concrete blocks as a raw material, (W) water and (C) cement and, in the case of the cement, (G) coarse aggregate which is obtained by crushing demolished concrete blocks and has a particle size of 40 mm. The amount of the cement compounded is such that the concrete has a uniaxial compressive strength exceeding 1 N/mm2 at the age of 28 days within the ranges of C/W0.5 and C/B0.5 on a mass basis.