[H-GM02_30PM1] Geomorphology

[HGM02-06] Experimental Study on Deterioration and Durability of Bicks due to Salts

Thi hai duong NGUYEN¹, *Chiaki T. OGUCHI² (1.Graduate School of Science and Engineering, 2.GRIS. Saitama University)

Keywords:salt weathering, brick, Vietnum, experiment, durability factor, salt susceptibility index

In Vietnam, heavy construction materials such as bricks are often used because there are many floods. However, the deterioration due to weathering has been found at general houses and historic brick buildings. To investigate deterioration of bricks used in these buildings, the present study performed salt weathering experiments using 6 bricks produced in Vietnam, Japan and China; red brick (RD), beige brick (BG), Vietnam brick (VN), amber brick (AB), brown brick (BR) and refractory brick (RF). These bricks were cut into cylindrical with a size of 3.5 cm in diameter and 7.0 cm in height. After examined rock properties such as physical, mechanical chemical and mineralogical characteristics, two types of salt weathering experiments were performed under 15-35℃ and 20℃ atmosphere. The saline solutions used in this study are 4%-Na₂SO₄, 8%-Na₂SO₄, 10%?Na2CO3. Results of the experiments show that the deterioration mechanism of bricks is explained that 1) when the salt is absorbed and crystallizes inside brick, micropores of brick are extended by crystal expansion pressure and make cracks, 2) strength of the brick increases slightly by salt crystallization, but decreases gradually by salt deliquescence, and 3) with repeating of 1) and 2), bricks will be damaged. Even chemical and the mineralogical characteristics are almost equal except for BG, physical and mechanical characteristics are deferent, which controls durabilities of these bricks.