HR: 1340h
AN: MR33A-0149    [Abstracts]
TI: Durability of building stones against artificial salt crystallization
AU: * Min, K
EM: kwmin@kangwon.ac.kr
AF: Kangwon National University, 192-1 Hyoja-2-dong, Chuncheon, 200-701 Korea, Republic of
AU: Park, J
EM: throb00@hanmail.net
AF: GAYA Engineering Co., Daeho B/D #422 Dogok-dong Gangnam-gu, Seoul, 135-270 Korea, Republic of
AU: Han, D
EM: handongyoul@hotmail.com
AF: Kangwon National University, 192-1 Hyoja-2-dong, Chuncheon, 200-701 Korea, Republic of
AB: Salts have been known as the most powerful weathering agents, especially when combined with frost action. Salt crystallization test along with freezing-thawing test and acid immersion test was carried out to assess the durability of building stones against weathering. Granite, limestone, marble and basalt were sampled from different quarries in south Korea for this study. One cycle of artificial salt crystallization test was composed of immersion of cored rock specimens in oversaturated solutions of CaCl₂, KCl, NaCl and Na₂SO₄, respectively for 15 hours and successive drying in an oven of 105°C for 3 hours and cooling at room temperature. Tests were performed up to 30 cycles, and specific gravity and ultrasonic velocity were measured after experiencing every 10 cycles and uniaxial compressive strength was measured only after 30 cycles. During the repeated Na₂SO₄ salt crystallization, some rock samples were gradually deformed excessively and burst after 20 to 30 cycles of test. The variation patterns of physical properties during the salt crystallization tests are too variable to generalize the effect of salt weathering on physical properties but limestone, marble and basalt samples showed relatively greater change of physical properties than granite samples. The recrystallized salts were well observed in the cracks of rock samples through the scanning electron microscope. In the all salt crystallization tests, apparent specific gravities for all tested samples increased generally but not so significantly due to recrystallization of salts. It can be inferred that filling the pores with salt crystals cause the increase of ultrasonic velocity during the early stage of salt crystallization and then in later stages the repeated cycles of salt crystallization result in development of cracks leading decrease of ultrasonic velocity for some rock samples.
DE: 5199 General or miscellaneous
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005