Correlations Between Slake-Durability Index and Engineering Properties of Some Travertine Samples Under Wetting–Drying Cycles

Abstract

Six travertine rock samples have been collected from different parts of Cheshmeh-Hafez quarry in northwest of Damghan, northern Iran. Physical and mechanical properties of the samples mean dry and saturated unit weights, specific gravity, porosity, water absorption, ultrasonic P wave velocity, Schmidt rebound hardness, point load index, Brazilian tensile strength, block punch index and uniaxial compressive strength have been determined according to the ISRM (in: Ulusay, Hudson (eds) Suggested methods prepared by the commission on testing methods, International Society for Rock Mechanics (ISRM), Kozan Offset, Ankara, 2007) standard in the laboratory. Also, slake-durability test was carried out up to ten cycles in different solutions. The used solutions were natural water with pH 7 of the region and sulfuric acidic solutions with pH of 5.5 and 4. Then empirical relationships by regression analyses were undertaken between the slake-durability indexes of all cycles of the test and measured physical and mechanical properties of the tested travertines. Regression analyses indicated that the relationships with correlation coefficients (R2) from 0.55 to 0.98 exist between slake-durability index and engineering properties of the rocks. The best and poor correlations were obtained between slake-durability index and specific gravity and block punch index, respectively. Results shown that in the first four wetting–drying cycles, the correlation coefficients between slake-durability index and physical properties of the rocks are rapidly increased, whiles the increasing rate of the correlation coefficients between slake-durability index and mechanical properties of the rocks is maximum in the first three cycles. Therefore, the first and second cycles of slake-durability test can’t able to present actual durability of the rocks.