The effect of brine waters on engineering characteristics changes of sandstones

In this research, the effect of salinity on engineering characteristics of sandstones is investigated. For this purpose, two sandstones from abutments and rock fill (Rip-Rap) of Vanyar dam (in Eastern Azerbaijan province) were selected in addition to three water samples (drinking water, semi-brine and brine) to saturate these rock samples. Water content, uniaxial compressive, point load, thawing and freezing, sound velocity, and durability tests were carried out on dry and saturated samples at different time intervals. After 5 months of submerging type 1 and 2 sandstones in brine water, the uniaxial compressive strength values were decreased 13 and 4%, respectively, and after 10 months to 12 and 0.2%, respectively, compared to those of samples prepared using drinking water. By increasing the salinity of the water, the durability values after 10 cycles changed from 2.3 to 4.2% and from 1.8 to 3.2% for sandstones types 1 and 2, respectively. The sound velocity in a dry sample of sandstones types 1 and 2 was measured as 4450 and 4950 m/sec, respectively, while they reached 4699 and 5255 m/sec, respectively, by increasing salinity. The results show that brine water almost has no effect on thawing and freezing.