Abstract
In the study application of volcanic scoria concrete to artificial reefs is investigated. Volcanic scoria is a natural volcanic product that shows light weight, mil/i-porous, and far-infrared irradiation characteristics. The properties of volcanic scoria concrete using Jeju scoria aggregate are evaluated by conducting a comprehensive series of tests on strength and void ratio. It is concluded that the volcanic scoria concrete has the sufficient strength of 4MPa-13MPa and adequate void ratio of $12\%-35\%$ to be accepted as artificial reef concrete. The field experiments are performed through observation by scuba diver's at the Seogwipo coast. Porous specimen and plane concrete specimen are prepared for comparison purposes. Seasonal changes of soft coral on the two series of test specimens were have been observed from Apr. 9, 2004 to Mar. 18, 2005. The soft coral is well grown on the porous specimen however there are no significant changes on the conventional plain concrete specimen. Thus it is concluded that the volcanic scoria concrete is highly suitable as artificial reef concrete.