Abstract
The other paper (part 1 : published in Feb. 1971) reported the plan of experiment and some of results and considerations of experiment, and this paper continued to the part 1. The subjects of this paper are shown as follows. (1) Relation between the age of strength test and the percentage of variation of weight (refer to 3.4 in the original). (2) Relation between the age of strength test and the speed of evaporation of water (refer to 3.5 in the original). (3) Relation between the percentage of variation of weight and the compressive strength (refer to 3.6 in the original). The conclusions of this paper are as follows. (1) The earlier the form is removed, the greater the evaporation of water occurs. When concrete is cured in high temperature and slow hardening cement is used, the nature as mentiond above occurs greatly. (2) The difference of quantity of water of concrete which comes on the differenct age of stripping of form remains in long term, and this difference of water affects on the strength of concrete in long age. (3) The earlier the form of concrete is removed, the greater water is evaporated. when concrete is exposed to wind or high temperature, the nature as mentioned above occurs clearly, and this difference of quantity of water-content is maintained in long term. (4) When concrete is kept under the cycle of drying and wetting condition in early age, the earlier the form of concrete is removed, the greater amplitude of variation of weight occurs. (5) When saeling compound is coated immediately after removal of form, the evaporation of water is lesser. Although this prevention of evaporation of water is not so much effective on strength. (6) In the term from seven days to six months, if water-contents of concrete is measuered, there is a little possibility to estimate the strength of concrete.
