[M-IS07] Geomaterials in cultural heritage: weathering, investigation techniques, and conservation

[MIS07-P01] Characterization of the pores and their impact on the infiltration of salt solutions in bricks used in historic brick buildings

Kotaro Yumoto², *Chiaki T. Oguchi¹ (1.Institute for Environmental Science and Technology, Graduate School of Science and Engineering, Saitama University, 2.Department of Engineering, Saitama University)

Keywords:Bricks, hydrophobic coating, aluminum sulfate , magnesium sulfate, salt weathering

From 2011 to 2016, extensive restoration work was carried out on the Old Shimotsuke Brick Kiln, one of Japan's designated important cultural properties. However, white salt deposits are accumulating in the gaps between the steel columns used for seismic reinforcement and the bricks and concrete around them. The salt contains aluminum, which was not confirmed in the pre-restoration research. In the present study, experiments were carried out to clarify the infiltration behavior of solutions containing aluminum and sulfate into the salt weathering of bricks. In parallel, the effectiveness of a hydrophobic treatment for bricks was also investigated. Three types of brick, old brick, commercial brick, and old brick with a hydrophobic coating, were cut into pieces of 5 x 5 x 15 cm and were placed in salt solutions of aluminum sulfate and magnesium sulfate at a depth of 3cm and dried at 50 ºC. The amount of aluminum salt solution infiltrated was less than that of the magnesium salt solution. The use of repellents was effective. These results indicate that the influence of aluminum sulfates is less than that of magnesium sulfates from the point of view of salt uptake affecting salt weathering.