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Title:	Development of the pull-off test and investigation of moisture damage effect on adhesion properties of nano-clay modified bitumen
Authors:	Hend Ali Elharari Omar (P65737)
Supervisor:	Nur Izzi Md. Yusoff, Dr.
Keywords:	Bitumen Asphalt emulsion mixtures
Issue Date:	2-Nov-2017
Description:	An asphalt mixture is commonly used to pave the top layer of roads. It is composed primarily of mineral aggregate bound with a bituminous binder. Various distresses brought about by weather conditions and/or traffic load are imposed on roads during their service lives. One such type of distress is loss of adhesion strength between the components of the mixture. Loss of adhesion between bitumen and additive is usually caused by water infiltration, and this type of distress can lead to a significant economic toll due to excessively high maintenance and rehabilitation costs. Much effort has been made to improve adhesion between the components of such mixtures; for example, bituminous binders can be added to enhance the adhesion strength of mixtures. The focus of this study is to improve adhesion strength through the addition of nano-clay to 60/70 penetration grade bitumen. The tests conducted in this study were pull-off tests, boiling-water tests (ASTM D3625), Vialit adhesion tests (EN 12272-3), and surface free-energy (SFE) tests. Atomic force microscopy (AFM) was used for nano-scale testing, and modified Lottman indirect tensile testing (AASHTO T 283) was then performed to investigate t he adhesion strength of the asphalt mixture. Since the importance of pull-off test for evaluating the adhesion was discovered and there was no test available to determine the pull-off force, a simple mould was designed and fabricated for that purpose. The capability of the developed test for determining the pull-off force of the bitumen was then verified. In this pull-off test, two types of substrates, stainless steel and granite, were investigated. Correlations between the results of the pull-off force and the consistency tests were investigated. In the pull-off test, three different additives: cement, hydrated lime and nano-clay, were added to the bitumen with additive percentages of 2 and 4% by weight of bitumen. The effects of short-term aging (STA) and long-term aging (LTA) were also evaluated using pull-off and consistency tests. The results exhibited good correlation between the results of consistency tests and pull-off tests when a stainless steel substrate was used. The correlations did show some variation, with the softening point test exhibiting the best correlation. This confirms the capability of the developed pull-off test to evaluate the fluidity of the binder when it was fabricated as a thin film; it also highlights the relationship between the adhesion strength and the fluidity of the binder. The results from pull-off tests on granite substrates showed a different trend in that the correlations were very low. Finally, tests were conducted on a mixture containing a nano-clay additive to investigate the effect of water on adhesion strength. The general results from multi-scale testing methods conducted in this study showed that the addition of 2 and 4% nano-clay produced a surprising improvement of antistripping in the results of all tests. The improvement varied between tests because the procedures for each test differed. Correlations between the tests results were also investigated, resulting in weak to strong variation due to differences in the test procedures and the properties of the materials used. However, there was a general conclusion that these tests have potential to evaluate moisture damage, and that nanoclay as an additive improves resistance against water effects. Furthermore, and surprisingly, nano-clay also reduced aging effects when the mixture was subjected to STA and LTA. The additive could thus be used as both an anti-stripping and an antiaging additive.,Certification of Master's/Doctoral Thesis" is not available
Pages:	235
Call Number:	TE275.O583 2017 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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