Durability monitoring on RC structures using “Shirasu concrete” in marine environment
ABSTRACT: A kind of the volcanic ashes called “Shirasu”, abundantly deposited due to a big pyroclastic flow in the southern part of Kyushu Island, Japan, in 20 to 100 thousand years ago, is one of the unused natural resources. Shirasu has high quantity of volcanic glasses in its mineral compositions and has pozzolanic reactivity. From previous studies, Shirasu concrete, in which Shirasu used as fine aggregate, has long-term durability concerning to salt attack, sulfate attack, reactivity of ASR, and etc. In this research, an exposure test of reinforced Shirasu concrete is carried out to clarify the durability in actual marine environments, using long size specimens which are set up straightly through splash, tidal, and under the sea zone. Though the experiment is still continuing, from the results of non destructive observations and monitoring data during 3 years exposure, high durability of Shirasu concrete against chloride-induced deterioration was confirmed.