MECHANISM OF EFFLORESCENCE ON HISTORICAL BRICK MASONRY BUILDINGS REINFORCED WITH CONCRETE : Influence of water content in brick on efflorescence

It is indicated that the reinforcement with concrete causes efflorescence and decay of brick because of alkali salts in cement. This paper explains the mechanism of efflorescence on historical brick masonry buildings reinforced with concrete. First, accelerated test method was developed so as to reproduce efflorescence on brick masonry wall reinforced with concrete. Second, we investigated relation between water content and rate of evaporation. It is considered that water did not move in a liquid condition in the brick below the water content of 4〜5Vol%. Finally, model wall specimen similar to actual historical brick masonry wall was made and accelerated test was carried out. And water content of each brick was continuously measured by TDR(Time Domain Reflectometry) method during the test. It is concluded that efflorescence did not occur 4〜5Vol% water content below because movable water in liquid phase was not present in the brick.