多孔質無機材料の凍結融解を伴わない凍害劣化とその評価法 : ALCを中心とした凍害メカニズムの検討

抄録

Recently, porous inorganic materials, such as ALC, have been used as external walls. In comparisson with usual concrete, porous inorganic materials are damaged by frost suddenly and severely, and mechanism of frost damage of porous materials are thought to be different from that of concrete. In this paper, a new test method, which gives specimen a thermal gradient and water supply, is proposed. Using this test method, one of the charasteric frost damage of porous materials is clalified, and the mechanism of frost damage is discussed. Analysis of test results revealed that ; (1) Some inorganic materials are damaged under the conition which exposes speciment thermal gradient and supplies water from warm side without freezing and thawing. This damage part is limited, and almost same as 0℃. (2) Sealed specimens are damaged under the one side freezing condition, and this critical degree of water content is lower than that of freezing and thawing condition. (3) Damage under the one side freezing condition have much to do with water absorbtion, and have less to do with duravility under freezing and thawing condition.