Abstract
As for historic structures, aged deterioration such as weathering is conspicuous on the surface of brick and stone structures. The purpose of the present study is to devise a tester which can measure surface strength distribution of structures by slight-destructive inspection. At the first stage, a tester was devised experimentally. Secondly, the actual sur-face strength and the effect of repairing chemical agent on terra cotta were tested, and the result demonstrated the possibility of definite evaluation of the relative strength and thickness of the glaze, and the relative strength of the foundation. Thirdly, a formula was drawn out for the estimation of absolute strength of surface material, trying to secure the stability of drilling speed. As a result, an accurate measurement of inner strength variation of relatively homogeneous materials (brick, stone, plaster, cement paste, and so on) was successfully demonstrated.
