Effect of pH Condition and Different Solution on the Slake Durability of Granitic Rocks

The slake durability (SD) of a rock is a vital engineering property relevant to its evaluation and estimation of its degradability due to mechanical and chemical breakdown. This study assesses the influence of pH of slaking fluid and different acidic solutions on slake durability of granitic rocks (fine-grained and porphyritic granite) by carrying out slake durability test (SDT) in acidic and basic conditions or environment. Petrographic analysis and basic laboratory tests such as porosity, water absorption capacity, density, and point load test, Schmidt rebound hammer were performed on the granitic rocks. The SDT was carried out in accordance with the standard procedure in distilled water and in different slaking fluids prepared by adding suitable amount of H 2 SO 4 and HNO 3 (representing acidic solutions) and NaOH (representing alkaline solutions) to distilled water. The SD of the granitic rocks was evaluated up to 8 cycles in acidic and basic solutions with pH ranging from 2 to 12. The slake durability index (SDI) of the granitic rocks range from very high to extremely high under the different pH and two acidic solutions. The lowest SDI was obtained when the pH of the testing fluid is 2 (both in H 2 SO 4 and HNO 3 solutions). However, as the pH of the slaking fluid > 2, the durability index of the granitic rocks becomes indistinct depending on the rock material properties rather than the slaking fluid pH. The SDI of the granitic rocks in H 2 SO 4 solution is greater than in HNO 3 solution at pH = 2. The granitic rocks have very high to extremely high durability. However, the granitic rock with coarse texture, low strength, high water absorption capacity and porosity is quite more liable to degradation in different environments.