مقايسه آزمايشگاهي تاثير استفاده از نانوسيليس و ژئوگريد بر رفتار خستگي مخلوط آسفالتي گرم

Laboratory Comparison of the Effect of Using Geogrid and Nano-Silica on the Fatigue Behavior of Hot Mix Asphalt

ﺗﻤﺮﮐﺰ روي اﻗﺪاﻣﺎﺗﯽ ﺑﺎ ﻫﺪف ﺗﻘﻮﯾﺖ و ﺑﻬﺒﻮد ﻻﯾﻪ آﺳﻔﺎﻟﺘﯽ ﺑﻪ ﻣﻨﻈﻮر اﻓﺰاﯾﺶ ﻋﻤﺮ روﺳﺎزي، اﻫﻤﯿﺖ ﺑﺴﺰاﯾﯽ دارد. از ﺟﻤﻠﻪ روشﻫﺎي اﻓﺰاﯾﺶ ﻋﻤﺮ روﺳﺎزي ﺑﺘﻦ آﺳﻔﺎﻟﺘﯽ در ﺑﺮاﺑﺮ ﺧﺮاﺑﯽﻫﺎي ﺳﺎزهاي ﮐﻪ در اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﻪ آﻧﻬﺎ ﭘﺮداﺧﺘﻪ ﺷﺪه اﺳﺖ ﺷﺎﻣﻞ روﯾﮑﺮد اﺻﻼح ﻣﺨﻠﻮط آﺳﻔﺎﻟﺘﯽ )ﺑﺎ اﺳﺘﻔﺎده از ﻧﺎﻧﻮﺳﯿﻠﯿﺲ( و ﻫﻤﭽﻨﯿﻦ، روﯾﮑﺮد ﺗﺴﻠﯿﺢ آﺳﻔﺎﻟﺖ )ﺑﺎ اﺳﺘﻔﺎده از ژﺋﻮﮔﺮﯾﺪ( ﻣﯽﺷﻮد. در اﯾﻦ ﭘﮋوﻫﺶ، ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از آزﻣﺎﯾﺶﻫﺎي ﺻﻮرتﮔﺮﻓﺘﻪ، ﺑﻪ ﺑﺮرﺳﯽ ﻣﯿﺰان اﻓﺰاﯾﺶ ﻋﻤﺮ ﺧﺴﺘﮕﯽ اﯾﻦ دو روﯾﮑﺮد و ﻣﻘﺎﯾﺴﻪ آﻧﻬﺎ ﺑﺎ ﻋﻤﺮ ﺧﺴﺘﮕﯽ ﻧﻤﻮﻧﻪﻫﺎي ﺷﺎﻫﺪ ﭘﺮداﺧﺘﻪ ﺷﺪه اﺳﺖ. ﺑﻪ ﻣﻨﻈﻮر ﺗﻌﯿﯿﻦ ﻋﻤﺮ ﺧﺴﺘﮕﯽ ﻣﺨﻠﻮطﻫﺎي آﺳﻔﺎﻟﺘﯽ، از آزﻣﺎﯾﺶ ﺧﺴﺘﮕﯽ ﺗﯿﺮﭼﻪ ﺧﻤﺸﯽ در ﺷﺮاﯾﻂ ﮐﺮﻧﺶ ﺛﺎﺑﺖ )در ﺳﻪ ﺳﻄﺢ 700 ،500 و 900 ﻣﯿﮑﺮوﮐﺮﻧﺶ( ﺑﻬﺮه ﮔﺮﻓﺘﻪ ﺷﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽدﻫﻨﺪ ﮐﻪ ﻋﻤﺮ ﺧﺴﺘﮕﯽ ﺑﺮاي ﻫﺮ دو ﻧﻤﻮﻧﻪ ﻣﺨﻠﻮطﻫﺎي آﺳﻔﺎﻟﺘﯽ اﺻﻼحﺷﺪه ﺑﺎ ﻧﺎﻧﻮﺳﯿﻠﯿﺲ و ﺗﺴﻠﯿﺢﺷﺪه ﺑﺎ ژﺋﻮﮔﺮﯾﺪ اﻓﺰاﯾﺶ ﻣﯽﯾﺎﺑﺪ. ﺑﺮاي ﻣﺜﺎل، در ﺳﻄﺢ ﮐﺮﻧﺶ 500 ﻣﯿﮑﺮوﮐﺮﻧﺶ، 5 درﺻﺪ ﻧﺎﻧﻮﺳﯿﻠﯿﺲ ﺣﺪود 193/9 درﺻﺪ )ﻣﻌﺎدل 2/94 ﺑﺮاﺑﺮ( و ﯾﮏ ﻻﯾﻪ ژﺋﻮﮔﺮﯾﺪ ﺣﺪود 212/4 درﺻﺪ ﻣﻌﺎدل 3/12 ﺑﺮاﺑﺮ( ﻋﻤﺮ ﺧﺴﺘﮕﯽ را ﻧﺴﺒﺖ ﺑﻪ ﻧﻤﻮﻧﻪﻫﺎي ﺷﺎﻫﺪ اﻓﺰاﯾﺶ ﻣﯽدﻫﻨﺪ. ﻫﻤﭽﻨﯿﻦ، ﻣﺨﻠﻮطﻫﺎي آﺳﻔﺎﻟﺘﯽ ﺗﺴﻠﯿﺢﺷﺪه ﺑﺎ ژﺋﻮﮔﺮﯾﺪ در سطح كرنش‌هاي مذكور، به ترتيب حدود 6.5 درصد (معادل 1.06 برابر)، 61 درصد (معادل 1.61 برابر) و 1.8 درصد (معادل 1.02 برابر) افزايش عمر خستگي مخلوط نسبت به نمونه‌هاي اصلاح‌شده با نانو سيليس گرديدند.

It is very important to focus on treatments aimed at strengthening and improving the asphalt layer to increase the life of the pavement. Among the methods to increase the life of asphalt concrete pavement against structural failures that have been discussed in this study include the asphalt mixture modification approach (using Nano-silica) as well as asphalt reinforcement approach (using geogrid). In this study, based on the results of previous studies, the increase in fatigue life of these two approaches and their comparison with the fatigue life of control samples has been investigated. To determine the fatigue life of asphalt mixtures, the fatigue test of 4 points bending (4PB) beams under constant strain conditions (at 3 levels of 500, 700 and 900 micro-strains) has been used. The results show that by addition (in wet method) of Nano-silica to pure bitumen, the fatigue life of asphalt mixture is increased for both samples of Nano-silica modified and geogrid reinforced asphalt mixtures. For example, at a strain level of 500 micro-strain, the addition of 5% Nano-silica increases the fatigue life by about 193.9% (equivalent to 2.94 times) and the installation of a geogrid layer increases the fatigue life by about 212.4% (equivalent to 3.12 times). Also, asphalt mixtures reinforced with geogrid at the strain levels of 500, 700 and 900, respectively, increased the fatigue life of the mixture by about 6.5% (equivalent to 1.06 times), 61% (equivalent to 1.61 times) and 1.8% (equivalent to 1.02 times) compared to the samples modified with Nano-silica.