Abstract
Ohya-Rock and Futatsui-Rock are famous kinds of zeolite rock. We have been studying how to use zeolite, which were found underground in Japan and China, for concrete materials. On our primary research we showed that zeolite had hydraulicity in calcium hydroxide. This paper presents the research on the effect of zeolite as a strength increasing admixture of concrete. Our investigation proved to be successful, and we were able to draw the following conclusions : (1) Ohya-Rock contains 60 % of clinoptilolite which is the principal mineral of rock. (2) Concrete replaced 10 % of cement by the zeolite powder, showed 10〜15 % higher compressive strength on 28 days as compared with the non-zeolite concrete. (3) To increase the fineness of zeolite powder was considered to be ineffective in incrementing the compressive strength of concrete. Therefore, the optimum fineness of zeolite powder seems to be 6@m. This value is approximatly the same as the fineness of cement. (4) The compressive strength test results of concrete showed that the highest value was obtained only by the specimens which were replaced by 10 % of the zeolite powder, and the specimens that were tested with 15 and 20 % proved to be ineffective. (5) The effect on the incrementation of the strength of concrete was the same in both specimens, which used ordinary portland cement and portland blast furnace slag cement, when the zeolite powder was used.
