ارزيابي آزمايشگاهي مخلوط‌هاي آسفالتي داغ حاوي گيلسونايت و الياف فورتا و تعيين منافع اقتصادي استفاده از آنها در روسازي‌هاي آسفالتي

Laboratory evaluation of hot asphalt mixtures containing Gilsonite and FORTA fibers and determination of economic benefits of their use in asphalt pavements

رﺷﺪ وﺳﺎﯾﻞ ﻧﻘﻠﯿﻪ در ﺳﺎلﻫﺎي اﺧﯿﺮ در ﮐﺸﻮرﻫﺎي در ﺣﺎل ﺗﻮﺳﻌﻪ ﻣﻨﺠﺮ ﺑﻪ اﻓﺰاﯾﺶ ﻫﺰﯾﻨﻪﻫﺎي راهﺳﺎزي و ﻧﮕﻬﺪاري آن ﺷﺪه اﺳﺖ. ﻟﺬا، اﺻﻼح ﺧﺼﻮﺻﯿﺎت ﻗﯿﺮ اﻣﺮي ﺿﺮوري ﻣﯽﺑﺎﺷﺪ. ﯾﮑﯽ از روشﻫﺎي اﺻﻼح ﺧﺼﻮﺻﯿﺎت ﻗﯿﺮ و آﺳﻔﺎﻟﺖ، اﺳﺘﻔﺎده از اﻧﻮاع اﻓﺰودﻧﯽﻫﺎ ﻣﯽﺑﺎﺷﺪ. اﯾﻦ اﻣﮑﺎن وﺟﻮد دارد ﮐﻪ ﻣﻮاد اﻓﺰودﻧﯽ، ﻫﺰﯾﻨﻪﻫﺎي ﻣﺎﻟﯽ را اﻓﺰاﯾﺶ دﻫﻨﺪ و ﺑﻨﺎﺑﺮاﯾﻦ اﺳﺘﻔﺎده از آﻧﻬﺎ را ﻏﯿﺮﻋﻤﻠﯽ ﮐﻨﻨﺪ. اﻣﺎ ﻣﻮاد اﻓﺰودﻧﯽ ﺧﺎﺻﯽ وﺟﻮد دارﻧﺪ ﮐﻪ ﻣﯽﺗﻮاﻧﻨﺪ در ﻣﺨﻠﻮط اﺳﺘﻔﺎده ﺷﻮﻧﺪ و ﻫﺰﯾﻨﻪﻫﺎي اﺿﺎﻓﯽ اﯾﺠﺎد ﻧﮑﻨﻨﺪ. در اﯾﻦ ﻣﻄﺎﻟﻌﻪ آزﻣﺎﯾﺸﮕﺎﻫﯽ، ﻋﻤﻠﮑﺮد اﻓﺰودﻧﯽﻫﺎي ﮔﯿﻠﺴﻮﻧﺎﯾﺖ و اﻟﯿﺎف ﻓﻮرﺗﺎ در ﻗﯿﺮ و ﻣﺨﻠﻮط آﺳﻔﺎﻟﺘﯽ ارزﯾﺎﺑﯽ ﺷﺪه اﺳﺖ. آزﻣﺎﯾﺶﻫﺎي ﻗﯿﺮ اﻧﺠﺎم ﺷﺪه در اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﺮ اﺳﺎس اﻓﺰودن ﮔﯿﻠﺴﻮﻧﺎﯾﺖ )ﺻﻔﺮ، 12 ،9 ،6 ،3 و 15 درﺻﺪ وزن ﻗﯿﺮ( اﺳﺖ. در ﺣﺎﻟﯽ ﮐﻪ آزﻣﺎﯾﺶﻫﺎي ﻣﺨﻠﻮط آﺳﻔﺎﻟﺘﯽ ﺑﺮ اﺳﺎس اﻓﺰودن اﻟﯿﺎف ﻓﻮرﺗﺎ )ﺻﻔﺮ، 0/6 ،0/3 و 0/9 درﺻﺪ وزن ﻣﺨﻠﻮط( اﻧﺠﺎم ﺷﺪه اﺳﺖ. ﻫﻤﭽﻨﯿﻦ، اﺛﺮ ﻣﺸﺘﺮك ﻫﺮ دو ﻣﺎده اﻓﺰودﻧﯽ ﺑﻪﻋﻨﻮان ﯾﮏ اﻓﺰودﻧﯽ ﮐﺎﻣﭙﻮزﯾﺖ ﺑﺮ ﻋﻤﻠﮑﺮد ﻣﺨﻠﻮطﻫﺎي آﺳﻔﺎﻟﺘﯽ ﻧﯿﺰ ارزﯾﺎﺑﯽ ﺷﺪ. ﻧﻤﻮﻧﻪﻫﺎ از ﻧﻈﺮ اﺳﺘﺤﮑﺎم ﻣﺎرﺷﺎل و ﺣﺴﺎﺳﯿﺖ رﻃﻮﺑﺘﯽ ﻣﻮرد آزﻣﺎﯾﺶ ﻗﺮار ﮔﺮﻓﺘﻨﺪ. در ﺣﺎﻟﯽ ﮐﻪ آزﻣﺎﯾﺶﻫﺎي ﺧﺴﺘﮕﯽ و ﺧﺰش دﯾﻨﺎﻣﯿﮏ ﺑﺎ اﺳﺘﻔﺎده از دﺳﺘﮕﺎه UTM اﻧﺠﺎم ﺷﺪ. ﻫﻤﭽﻨﯿﻦ، ﺟﻨﺒﻪﻫﺎي اﻗﺘﺼﺎدي اﺳﺘﻔﺎده از اﯾﻦ دو اﻓﺰودﻧﯽ ﻧﯿﺰ در ﺗﺤﻘﯿﻖ ارزﯾﺎﺑﯽ ﮔﺮدﯾﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ اﺳﺘﻔﺎده از ﮔﯿﻠﺴﻮﻧﺎﯾﺖ در ﻗﯿﺮ ﺑﺎﻋﺚ اﻓﺰاﯾﺶ اﺳﺘﺤﮑﺎم ﻣﺎرﺷﺎل، ﻣﻘﺎوﻣﺖ در ﺑﺮاﺑﺮ ﺧﺴﺘﮕﯽ و ﺷﯿﺎرﺷﺪﮔﯽ و ﮐﺎﻫﺶ ﺣﺴﺎﺳﯿﺖ رﻃﻮﺑﺘﯽ ﻣﺨﻠﻮطﻫﺎي آﺳﻔﺎﻟﺘﯽ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ اﻟﯿﺎف ﻓﻮرﺗﺎ در ﻣﺨﻠﻮطﻫﺎي آﺳﻔﺎﻟﺘﯽ ﻣﯽﺷﻮد. ﻫﻤﭽﻨﯿﻦ، ﺑﻬﺘﺮﯾﻦ درﺻﺪ ﻣﺸﺘﺮك ﮔﯿﻠﺴﻮﻧﺎﯾﺖ و اﻟﯿﺎف ﻓﻮرﺗﺎ در ﻧﻤﻮﻧﻪﻫﺎي ﺳﺎﺧﺘﻪ ﺷﺪه ﺑﻪ ﺗﺮﺗﯿﺐ در 15% و 0/9 درﺻﺪ اﺗﻔﺎق اﻓﺘﺎده اﺳﺖ. ﻧﺘﺎﯾﺞ آﻧﺎﻟﯿﺰ اﻗﺘﺼﺎدي ﻧﺸﺎن داد ﮐﻪ اﻓﺰودن %15 ﮔﯿﻠﺴﻮﻧﺎﯾﺖ ﺑﻪ ﻗﯿﺮ از ﻧﻈﺮ اﻗﺘﺼﺎدي ﮐﺎرآﻣﺪ و در ﻋﻤﻞ ﻗﺎﺑﻞ ﺗﻮﺟﯿﻪ اﺳﺖ.

The growth of vehicle traffic in recent years in developing countries has led to an increase in the costs of road building and maintenance. Therefore, modification of bitumen properties is necessary due to the poor quality of bitumen. In this lab study, the relative performances of Gilsonite and FORTA fibers modifiers are evaluated. The bitumen tests conducted for this research are based on the addition of Gilsonite (0, 3, 6, 9, 12 and 15 % of made bitumen specimens), while the asphalt mixture tests are based on the addition of FORTA fibers (0, 0.3, 0.6, and 0.9% by weight of aggregate). The synergistic effect of adding both the additives as a composite additive on the relative performance of asphalt mixtures is also evaluated. The samples were tested for Marshall Stability and moisture sensitivity, while fatigue and dynamic creep tests were performed using the UTM machine. The results showed that only the use of Gilsonite as a modifier in bitumen significantly increases the Marshall Stability, fatigue resistance, the flow value resulted from dynamic creep tests and decrese moisture sensitivity of the asphalt mixtures compared to the use of FORTA fibers as a modifier in the mixture.