بررسي ويژگيهاي مهندسي نمونه هايي از سنگ هاي ساختماني در چرخه هاي انجماد و ذوب آب

Investigation of Engineering Properties of some samples from Building Stones in Cycles of Freeze-thaw

Rocks are natural materials which are used in a variety of engineering constructions, especially in buildings. Freeze-thaw is one of the most important environmental agents which causes change in the engineering properties, strength and durability span of rocks. In this study 14 samples of building stones with different origins were selected, then freeze-thaw test up to 30 cycles were performed and values the engineering properties of these rocks including Brazilian tensile strength, point load strength index and P-wave velocity, after every 5 cycles were determined. Results show that with increasing freeze-thaw cycles, the values of these properties have been decreased. Also, samples which had the effective porosity more than 1%, their Brazilin tensile strength, point load strength index and P-wave velocity have been more decreased. Moreover, results indicated that effective porosity had more important role than the both mineral composition and rock origin in changes of engineering properties of samples in freeze- thaw test. Accordingly, the most suitable rocks for use in regions with probability of freeze-thaw were recommended