Evaluation of Relation between Sedimentary Rocks Age and Durability of Them in Deteriorate Environments

Sedimentary rocks are the most common rocks exposed on the Earth’s surface and most of the civil structures are located on them, so the identification of these rocks have great importance. This recognition is more important in destructive environments such as beaches. One of the most important factor on the engineering parameter results is the age of sedimentary rocks. In this study, beside the evaluation and field study of breakwaters in the southern and northern coasts of Iran, lithological and structural characteristics of materials were studied. Also, the purpose of this study was to determine and evaluate the engineering properties of stone materials based on engineering experiments to help evaluate durability and compare them with the results of field evaluation of actual rock performance. But the most important part of studies is to evaluate the effect of rock ages on the results and performance of these materials. The results show that materials with a siliceous composition such as sandstone compared to carbonate materials are the same in geological age. Also, increasing the age of rock materials (from Pleistocene to Cretaceous) causes an increase in rock density (from 1.59 to 2.45 g/cm3), reduced porosity (from 44.7 to 0.41%) and water absorption (from 29.6 to 0.21%), increase in strength parameters including increase in uniaxial compressive strength (from 5 to 111.19 MPa), increase in point load test (from 1.2 to 5.12 MPa) and increase in tensile strength (from 0.10 to 16.56 MPa) and decrease in durability due to abrasion, impact and chemical processes, including decrease in impact value (from 54.30 to 10.94%), increase in slake durability index (from 82.10 to 99.44%), a decrease in soundness (from 28.50 to 0.038 %) and a decrease in Los Angeles abrasion test (from 71.57 to 22.67%).