ارتباط بين شاخص ساختار - ترافيك و عملكرد روسازي‌ جاده‌هاي روستايي

The correlation between the structure-traffic index and pavement performance in the rural roads

ساختار لايه اي روسازي راه هاي روستايي تحت ترافيك سنگين به دليل رعايت هم زمان مسائل اقتصادي و فني داراي اهميت خاصي است. در اين پژوهش با بررسي مطالعه موردي روسازي يك راه روستايي، مدلهاي مختلف لايه اي يك راه تحت عبور ترافيك تريلرهاي كشاورزي بررسي - شده است. براي شناسايي كردن مدلهاي مختلف راه از شاخص ساختار ترافيك STI استفاده شده است. اين شاخص از تقسيم عدد سازه اي روسازي بر مجذور پارامتر بارگذاري ترافيك بدست ميآيد در ابتدا با استفاده از مدلسازي در نرمافزار المان محدود آباكوس مشخص شد كه تريلرهاي 72 چرخ با محور تريدم اثر مخربتري نسبت به تريلرهاي 18 چرخ با محور تاندم روي روسازي دارند و تريلر اسكانيا جي، به عنوان تريلر بحراني مبناي محاسبات قرار گرفت. سپس مدلهاي مختلف روسازي براي خرابي خستگي و شيارشدگي به صورت جداگانه در اثر عبور 23سانتيمتري در ضخامت آسفالت گرم باعث / تريلر بحراني بررسي شد. در مدلسازي سناريوهاي مختلف براي مدل راه مشاهده شد كه افزايش 2/5 درصد كاهش تنش كششي زير لايه آسفالت ميشود و همچنين افزايش 5 سانتيمتري آن باعث 41 درصد كاهش در اين تنش ميشود. همچنين در اين پژوهش سعي شده است به تاثير لايههاي مختلف روسازي در كاهش پارامترهاي خرابي شيارشدگي و خستگي پرداخته شود كه مهمترين آن، تاثير قابل ملاحظه لايه آسفالت سرد در كاهش خرابي شيارشدگي است به طوري كه حتي استفاده از لايه آسفالت سرد از اجراء مجموع دو لايه اساس و زيراساس، باعث كاهش پارامتر خرابي شيارشدگي به ميزان % 15 است.

Layer structure of rural roads under heavy traffic has essential importance because of simultaneous observing of economic and technical issues. In this study with investigating a case study of a rural road, different structure models of layers a road under traffic Agricultural trailers have been investigated. To identify different models of the road of structure-traffic index (STI) is used. At first, it is specified that 12 wheels trailers with tridem axle have more destructive effect on the pavement relation to 18 wheels trailers with tandem axle, by the modeling of finite element software ABAQUS; and the Scania G400 placed for the base calculation as a critical trailer. Then different road models is investigated separate for fatigue and rutting distress under crossing of critical trailer. The modeling critical trailer load on the different road models show that there is a Exponential relationship between STI index and fatigue and rutting distress with acceptable accuracy. This relationship is indirect for the fatigue distress with changes constant equal to 13.76. In contrast, this relationship is direct for the rutting distress with changes constant equal to 135.31 that show rutting has more influence of STI index changes relation to fatigue. Also in this study, it is tried to investigate different layer efficiency of pavement in reducing agents related with rutting and fatigue damage that the most important matter is remarkable effect cold asphalt on the rutting reducing so that even cold asphalt layer is more effective to reduce rutting distress parameter relation to sub base and base layers with together. Layer structure of rural roads under heavy traffic has essential importance because of simultaneous observing of economic and technical issues. In this study with investigating a case study of a rural road, different structure models of layers a road under traffic Agricultural trailers have been investigated. To identify different models of the road of structure-traffic index (STI) is used. At first, it is specified that 12 wheels trailers with tridem axle have more destructive effect on the pavement relation to 18 wheels trailers with tandem axle, by the modeling of finite element software ABAQUS; and the Scania G400 placed for the base calculation as a critical trailer. Then different road models is investigated separate for fatigue and rutting distress under crossing of critical trailer. The modeling critical trailer load on the different road models show that there is a Exponential relationship between STI index and fatigue and rutting distress with acceptable accuracy. This relationship is indirect for the fatigue distress with changes constant equal to 13.76. In contrast, this relationship is direct for the rutting distress with changes constant equal to 135.31 that show rutting has more influence of STI index changes relation to fatigue. Also in this study, it is tried to investigate different layer efficiency of pavement in reducing agents related with rutting and fatigue damage that the most important matter is remarkable effect cold asphalt on the rutting reducing so that even cold asphalt layer is more effective to reduce rutting distress parameter relation to sub base and base layers with together.