TY - JOUR
T1 - Use of microbially desulfurized rubber to produce sustainable rubberized bitumen
AU - Kabir, Sk Faisal
AU - Zheng, Renfei
AU - Delgado, Anca G.
AU - Fini, Elham H.
N1 - Funding Information:
This research was sponsored by the National Science Foundation (Award Numbers 1935723 and 1928795) and startup funds to Anca Delgado from Arizona State University. The authors acknowledge Evelym M. Miranda for help with sulfate concentration measurements and Daniel Burnett withSurface Measurement Systems foranalyzing the surface energy of the crumb rubber.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/1
Y1 - 2021/1
N2 - This paper examines the merits of using microbially desulfurized rubber to enhance theperformance ofbituminous pavements and promote recycling of scrap tires. To prepare microbially desulfurized rubber, we incubated crumb rubber obtained from waste tiresin medium with microbes from waste activated sludge. The concentration of sulfate was monitored during the treatment process and desulfurization was estimated to be about34%.Microbially desulfurized crumb rubber (MDR) was then added to bitumen to produce rubberized bitumen. Performance of the rubberized bitumen was compared with those of conventional crumb rubber modified (CRM) bitumen. To do so, Fourier transform infrared spectroscopy (FTIR), inverse gas chromatography (IGC), and rheometry were utilized. Chemical analysis of rubber particles after desulfurization showed a significant reduction of the peak at 500-540 cm−1; this was attributed to the breakage of disulfide bonds after microbial desulfurization. Measurement of surface energy showed that the acid-base component of surface energy increased three times (increasing from 1.85mJ/m2 to 5.55mJ/m2) after desulfurization. Such enhancement could lead to increased interactions between rubber and bitumen reducing their separation. This was evidenced ina68% reduction inseparation indexin bitumencontaining microbially-treated (desulfurized) rubber compared to bitumen havingnon-treated rubber. In addition, study results showed a 6% increase in elastic recovery,a 27% increase in resistance to moisture diffusion,a 12.5% decrease in viscosity,a 10% increase in stiffness, and a 5% increase in stress relaxation capacity compared to bitumen's having non-treated rubber. The outcome of the study promotes resource conservation by offering a simultaneous solution for recycling of scrap tire via a low-cost bio-inspired approach while enhancing pavement performance.
AB - This paper examines the merits of using microbially desulfurized rubber to enhance theperformance ofbituminous pavements and promote recycling of scrap tires. To prepare microbially desulfurized rubber, we incubated crumb rubber obtained from waste tiresin medium with microbes from waste activated sludge. The concentration of sulfate was monitored during the treatment process and desulfurization was estimated to be about34%.Microbially desulfurized crumb rubber (MDR) was then added to bitumen to produce rubberized bitumen. Performance of the rubberized bitumen was compared with those of conventional crumb rubber modified (CRM) bitumen. To do so, Fourier transform infrared spectroscopy (FTIR), inverse gas chromatography (IGC), and rheometry were utilized. Chemical analysis of rubber particles after desulfurization showed a significant reduction of the peak at 500-540 cm−1; this was attributed to the breakage of disulfide bonds after microbial desulfurization. Measurement of surface energy showed that the acid-base component of surface energy increased three times (increasing from 1.85mJ/m2 to 5.55mJ/m2) after desulfurization. Such enhancement could lead to increased interactions between rubber and bitumen reducing their separation. This was evidenced ina68% reduction inseparation indexin bitumencontaining microbially-treated (desulfurized) rubber compared to bitumen havingnon-treated rubber. In addition, study results showed a 6% increase in elastic recovery,a 27% increase in resistance to moisture diffusion,a 12.5% decrease in viscosity,a 10% increase in stiffness, and a 5% increase in stress relaxation capacity compared to bitumen's having non-treated rubber. The outcome of the study promotes resource conservation by offering a simultaneous solution for recycling of scrap tire via a low-cost bio-inspired approach while enhancing pavement performance.
KW - Activated sludge
KW - Bitumen
KW - Crumb rubber
KW - Microbial desulfurizing
KW - Segregation
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U2 - 10.1016/j.resconrec.2020.105144
DO - 10.1016/j.resconrec.2020.105144
M3 - Article
AN - SCOPUS:85089954015
SN - 0921-3449
VL - 164
JO - Resources, Conservation and Recycling
JF - Resources, Conservation and Recycling
M1 - 105144
ER -