Abstract
Shirasu is a kind of volcanic ashes, and is widely distributed in South Kyushu. It has a little lower melting and frothing temperature in comparison with other materials of artifical lightweight aggregate, and in homogeneous nature it can be mined at once abundantly and easily. The author has hit upon on idea that he will be able on that account to get a low-priced artificial lightweight aggregate made from Shirasu, and has manufactured for trial artificial lightweight sand and gravels (a tentative name; Calderite).
Then, the author made an experiment on the basic data of the properties for aggregate, statical properties and elastic properties, and ascertained its practicability. Calderite sand belongs to 2 sort, C class on classification of JIS A 5002. But, Calderite sand seems to come a little short of the requisite strength of aggregate for fine aggregate of structural concrete, so it is necessary to make further studies of the formula of manufacturing. Calderite gravel belongs to 2 sort, C class or 3 sort, C class on classification of JIS A 5002. The author has proved that Calderite aggregate concrete can adequately be put to use, upon comparison with every standard from the results of the experiment on statical properties and elastic properties of Calderite aggregate concrete.
But, Calderite manufactured for trial in generally felt a little soft and brittle. Then, it is necessary to study further as to the temperature in kiln and formula of manufacturing etc., and if so, it is hoped that the improvement of its quality will be made accordingly.
