1 AIT Asian Institute of Technology

Investigating moisture sensitivity of nano-cellulose modified asphalt mixture using loose mixture tests and surface free energy measurements

AuthorNawaz, Shaik Mohammed Asif
Call NumberAIT Thesis no.TE-17-16
Subject(s)Cellulose--Chemistry
Pavements, Asphalt--Additives--Testing

NoteA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Transportation Engineering
PublisherAsian Institute of Technology
AbstractThe harmful effect of water in the asphalt pavement system is found to be the result of the synergistic action of several mechanisms such as detachment, displacement, pH of water, hydraulic scouring and action of pore pressure build up. These mechanisms are dependent on several factors when preparing the asphalt mixture to lay a pavement, factors such as viscosity, wettability of binder and adhesion and cohesion of binder with aggregate. Hence, variety of additives are used to mitigate the harmful effects of water such as hydrated lime and amine based anti-strip additives. This study tries to quantify moisture sensitivity of mixtures prepared by adding new additive, nanocellulose to the base or control binder. The main objective of the study to modify binder using nanocellulose is achieved by surface modification of nanocellulose called silylation, and the process successfully helped disperse nanocellulose homogenously in polymeric matrix of asphalt binder. To quantify moisture sensitivity of nanocellulose modified binder, 6 binders were prepared, the control binder, CNF modified binder consisting (0.2%, 0.4%, 0.6% and 0.8% conc. by weight) and a hydrated lime (1% conc by weight) modified binder to compare the nanocellulose to traditional modifications. The qualitative methods followed to quantify the moisture sensitivity of modified binders in this study consist modified boiling water test and asphalt bond strength test and to support and validate the results of qualitative tests surface free energies of all binders and aggregates were estimated using sessile drop method (static contact angle) individually to estimate the surface energy of interfaces formed at combination of modified binder and granite or limestone aggregate. The results of modified boil test and ABS test show that nanocellulose modified binder especially the 0.6% and 0.8% CNF modified binder showed a drastic improvement by retaining more on aggregate surface and displaying highest pull of tensile strength respectively and these binders in combination with limestone showed least % loss in pull of tensile strength after moisture conditioning compared to other combinations. This behavior of improvement in qualitative test is further supported by surface energy measurements indicating the increase in work of adhesion and cohesion values on increasing the concentration of nanocellulose in binder. Work of debonding values were used to understand the behavior of wet conditioned samples i.e., adhesion of interface in the presence of water in system. The SFE measurements showed high correlation with physical tests like rotational viscosity and asphalt bond strength test which supported the results of both boiling water tests and asphalt bond strength tests
Year2018
TypeThesis
SchoolSchool of Engineering and Technology
DepartmentDepartment of Civil and Infrastucture Engineering (DCIE)
Academic Program/FoSTransportation Engineering (TE)
Chairperson(s) Kunnawee Kanitpong;
Examination Committee(s)Hornyak, Gabriel Louis;Bora, Tanujjal;Surachet Pravinvongvuth;
Scholarship Donor(s)Asian Institute of Technology Fellowship;
DegreeThesis (M.Eng.) - Asian Institute of Technology, 2018


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