Estimation method of stress and strain history in cement-based composite materials and calcite particle aggregates

An estimation method of stress and strain history regarding to an object to be measured (50) in which a plurality of calcite particles (11) having a particle diameter of a predetermined size are embedded as a stress sensor,

• wherein a plurality of the calcite particles (11) are calcite particles with no twin crystals that are mixed in a predetermined mixing ratio in a cement composite material (12) prepared in advance so that an elastic modulus becomes a predetermined value in a solidified state to be formed into a predetermined shape of a calcite particle aggregates (10) as a whole, and one or more of the calcite particle aggregates (10) are removably embedded in the object to be measured (50) with non-shrinkage mortar (60), and
• the calcite particle aggregates (10) after receiving an external force are processed to be extracted as a portion of the non-shrinkage mortar (60) from the object to be measured (50), and to be cut out to expose crystal planes of the calcite particles (11) so that a twin-crystal density (Dtw) thereof is measured, wherein the twin-crystal density (Dtw) is to be converted into strain (ε) based on an approximate formula showing a relationship between strain (ε) and twin-crystal density (Dtw), and the strain (ε) is to be converted into stress (σ) based on the elastic modulus.