Seal binder rheology at intermediate temperatures and influence on stone orientation

Van der Spuy, Herline (2022-04)

Thesis (MEng)--Stellenbosch University, 2022.

Thesis

ENGLISH ABSTRACT: The conditions of seal binders at intermediate temperatures are important to consider when constructing a road. The condition of a binder at construction time influences the performance of the binder in its lifetime. The intermediate temperature conditions of a binder, at construc tion time, influences the road performance. Previous work has failed to address how the creep and recovery of a binder at intermediate temperatures influences the performance of the binder for the long-term. The approach to this study was to evaluate different types of binders used in South Africa, and their performance at various temperatures, with the focus on intermediate temperatures. Original and short-term aged conditions were evaluated to cover the property changes from the refinery to the construction period. The creep and recovery characteristics are analysed to de termine the behaviour of the binder, and how it could link to stone orientation. The materials used in this study was an unmodified binder and four modified binders. The modified binders consisted of two elastomers and two rubber binders. The Bending Beam Rheometer was used to obtain data at cold temperatures, and the Dynamic Shear Rheometer for intermediate and high temperatures. The Multiple Stress Creep and Recovery (MSCR) test was used to obtain the non-recoverable creep compliance (Jnr and the recovery (%R)). Results showed that the type and degree of modification significantly influences the perfor mance of binders at intermediate temperatures. The modified binders demonstrated character istics that would increase the relationship between the binder and stones, which would affect stone orientation in the surface layer.

AFRIKAANSE OPSOMMING: Die toestand van bitumin-bindmiddels by intermediêre temperature is belangrik om in ag te neem wanneer ’n pad gebou word. Die toestand van ’n bindmiddel tydens konstruksietyd beïn vloed die werkverrigting van die bindmiddel in sy leeftyd. Die intermediêre temperatuurtoes tande van ’n bindmiddel, tydens konstruksietyd, beïnvloed die padverrigtinge. Vorige werk het versuim om aan te spreek hoe die kruip en herstel van ’n bindmiddel by intermediêre tempera ture die werkverrigting van die bindmiddel vir die langtermyn beïnvloed. Die benadering tot hierdie studie was om verskillende tipes bindmiddels wat in Suid-Afrika gebruik word, en hul werkverrigting by verskillende temperature te evalueer, met die fokus op intermediêre temperature. Oorspronklike en korttermyn-verouderde toestande is geëvalueer om die eienskap-veranderinge van die raffinadery tot die konstruksietydperk te dek. Die kruip en herstelkenmerke word ontleed om die gedrag van die bindmiddel te bepaal, en hoe dit met kliporiëntasie kan skakel. Die materiaal wat in hierdie studie gebruik is, was ’n ongemodifiseerde bindmiddel en vier gemodifiseerde bindmiddels. Die gemodifiseerde bindmiddels het bestaan uit twee elastomere en twee rubberbinders. Die Buigbalk Rheometer is gebruik om data by koue temperature te verkry, en die Dynamic Shear Rheometer vir intermediêre en hoë temperature. Die Multiple Stress Creep and Recovery (MSCR)-toets is gebruik om die nie-herstelbare kruip-nakoming (Jnr en die herstel (%R)) te verkry. Resultate het getoon dat die tipe en graad van modifikasie die werkverrigting van bindmid dels by intermediêre temperature aansienlik beïnvloed. Die gemodifiseerde bindmiddel het kenmerke getoon wat die verhouding tussen die bindmiddel en klippe sou verhoog, wat kli poriëntasie in die oppervlaklaag sou beïnvloed.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/124804
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