معرفي پارامتر فيزيكو-مكانيكي براي برآورد دوام سنگ‌هاي تراورتن ‌ در برابر هوازدگي نمك

Introducing the physico-mechanical parameter for estimating the durability of travertine stones against weathering salt

دوام سنگ­ها در برابر عوامل مخرب محيطي از مهمترين موضوعات مرتبط با انتخاب سنگ براي استفاده در سازه­هاي مهندسي به ويژه سنگ نماي ساختمان­ها مي­باشد. تبلور نمك­هاي محلول يكي از مهمترين عوامل هوازدگي در طبيعت است كه مي­تواند بر خصوصيات مكانيكي سنگ (مانند مقاومت فشاري تك محوري و مقاومت كششي برزيلين) تاثير بگذارد و در طول زمان باعث زوال­پذيري و كاهش دوام آن شود. در اين پژوهش پارامتر فيزيكو-مكانيكي معرفي شده است كه مي­تواند خصوصييات مكانيكي سنگ­ها و در نتيجه دوام آن­ها را در برابر هوازدگي نمك با دقت و صحت مناسب برآورد كند. به منظور رسيدن به اهداف پژوهش، 15 نمونه تراورتن از معادن مختلف ايران انتخاب شد. از تراورتن­ها نمونه ­ها و مغزه ­هاي لازم براي تعيين خصوصيات فيزيكي (جذب آب، ميانگين قطر حفره­هاي نمونه­ها) و خصوصيات مكانيكي (مقاومت فشاري تك محوري و كششي برزيلين) تهيه و مقادير اين خصوصيات تعيين شد. سپس مقادير پارامتر فيزيكو-مكانيكي كه بر اساس تركيبي از جذب آب، ميانگين قطر حفره­ها و خصوصيات مكانيكي مي­باشد، محاسبه شد. با انجام آناليزهاي رگرسيون دو متغيره، رابطه بين مقادير پارامتر فيزيكو-مكانيكي با مقادير مقاومت فشاري تك محوري و كششي برزيلين بعد از آزمايش هوازدگي نمك بررسي و مناسبترين روابط براي برآورد دوام نمونه­ هاي مورد مطالعه با استفاده از پارامتر فيزيكو - مكانيكي در برابر هوازدگي نمك ارائه شده است. نتايج نشان دهنده دقت و صحت مناسب پارامتر فيزيكو-مكانيكي براي برآورد دوام نمونه­ هاي مورد مطالعه مي­باشد. در نهايت با استفاده از پارامتر فيزيكو - مكانيكي معرفي شده در پژوهش حاضر، مي­توان از انجام آزمايش زمانبر و پرهزينه هوازدگي نمك صرفنظر كرد.

The durability of stone against environmental degradation factors is one of the most important issues related to stone selection for use in engineering structures, in particular stone stones. The crystallization of soluble salts is one of the most important weathering factors in nature, which can affect the mechanical properties of rock (such as uniaxial compressive strength and Brazilian tensile strength) and, over time, can decay and reduce its durability. In this research, a physico-mechanical parameter has been introduced that can assess the mechanical properties of rocks and thus their durability against salt weathering with accurate accuracy. To achieve the research objectives, 15 travertine samples were selected from different mines in Iran. Travertine samples were prepared to determine the physical properties (water absorption, mean pore diameter) and mechanical properties (uniaxial compressive strength and Brazilian tensile strength). Then, the physico-mechanical parameter was calculated, based on the combination of water absorption, mean diameter of the pores and mechanical properties. By performing bivariate regression analysis, the relationship between physico-mechanical parameter with uniaxial compressive strength and Brazilian tensile strength after the salt weather test was investigated and the most suitable relationships for estimating the durability of the samples using a physico-mechanical parameter against weathering is presented. The results show the correct accuracy of the physico-mechanical parameter for estimating the durability of the studied samples. As a result, the Physico-Mechanical Parameter avoids performing a salt crystallization test, which is time-consuming and expensive. The durability of stone against environmental degradation factors is one of the most important issues related to stone selection for use in engineering structures, in particular stone stones. The crystallization of soluble salts is one of the most important weathering factors in nature, which can affect the mechanical properties of rock (such as uniaxial compressive strength and Brazilian tensile strength) and, over time, can decay and reduce its durability. In this research, a physico-mechanical parameter has been introduced that can assess the mechanical properties of rocks and thus their durability against salt weathering with accurate accuracy. To achieve the research objectives, 15 travertine samples were selected from different mines in Iran. Travertine samples were prepared to determine the physical properties (water absorption, mean pore diameter) and mechanical properties (uniaxial compressive strength and Brazilian tensile strength). Then, the physico-mechanical parameter was calculated, based on the combination of water absorption, mean diameter of the pores and mechanical properties. By performing bivariate regression analysis, the relationship between physico-mechanical parameter with uniaxial compressive strength and Brazilian tensile strength after the salt weather test was investigated and the most suitable relationships for estimating the durability of the samples using a physico-mechanical parameter against weathering is presented. The results show the correct accuracy of the physico-mechanical parameter for estimating the durability of the studied samples. As a result, the Physico-Mechanical Parameter avoids performing a salt crystallization test, which is time-consuming and expensiv