Slake durability evaluation of granitic rocks under dry conditions and slaking solution and its prediction using petrographic and strength characteristics

In this paper, eight samples of different granitic rocks were selected from the Borujerd area in Lorestan Province, western Iran. Petrographic studies were performed, and some of their mineralogical indices [i.e., Feldspathic Index (IF), Colouration Index (IC), and Quartz-Feldspar Index (IQF)], and textural indices [i.e., Texture Coefficient (TC), Index of Interlocking (g), Index of Grain Size Homogeneity (t), and Index of Mean Grain Size (MGS)] were determined. Furthermore, the samples’ strength was measured by point load test. Afterward, the slake durability tests under dry conditions (i.e., without test solution), distilled water, and Na₂SO₄ solution were carried out for up to 120 cycles. Through these tests, the slake durability index (SDI) of the samples was determined every 20 cycles. The results revealed that the durability behavior is more influenced by their IQF, t, MGS, and strength than other mineralogical and textural indices. The SDI values obtained from slake durability tests under dry conditions and distilled water showed that the samples’ decay was significantly affected by the test specimens’ abrasion. In comparison, the wetting-drying cycles played a negligible role in the samples’ decay. Regression analyses revealed that samples’ SDI could be predicted using their IQF, t, MGS, and strength with different accuracy levels. Consequently, regression equations provide significant practical advantages for a rapid durability assessment of granitic rocks. Moreover, they save the long time necessary for performing slake durability tests.

• The mineralogical and textural indices and strength of different granitic rocks were determined.

• The SDTs under dry conditions, distilled water, Na₂SO₄ solution were carried out.

• The wetting–drying cycles played a slight role on the samples’ decay.

• The slake durability behavior of the samples is more influenced by their IQF, t, MGS, and strength.

• Regression Eqs. provide notable practical advantages for a rapid long-term slake durability.