The performances of asphalt concretes are typically influenced by the quantity and quality of filler, which is the aggregate with particle diameter of less than 0.075 mm. Large amounts of filler change the rheological behaviour and limit the possibility of movement for the bitumen, which is blocked by the filler particles. This study evaluated the behaviour of asphalt mastics (bitumen plus filler) in the linear viscoelastic region, mixing various types of binder with different fillers. Bitumens produced in Italy with penetration 50-70 and 70-100 0.1xmm were used. The fillers were selected in order to represent two types of material, a common construction product (cement) and a conventional by-product often processed as a waste (municipal solid waste incinerator ash). The amount of filler added to the bitumen varied from 0 to 100% by weight of bitumen. Tests were performed using a dynamic shear rheometer with two geometries, in amplitude and frequency sweep, with temperature scales between 15 °C and 70 °C. The tests verified that with a high filler content (100% by weight) the behaviour of mastic changes radically, due to the reduction of mobility and higher viscosity induced by the filler. The SHRP-derived Christensen-Anderson model, which can be conventionally used for describing the behaviour of mastics with a low percentage of filler, is not suitable for mastics with the characteristics analysed.

Analysis of the linear viscoelastic behaviour of bitumen with high quantities of filler

PASETTO, MARCO;GIACOMELLO, GIOVANNI
2016

Abstract

The performances of asphalt concretes are typically influenced by the quantity and quality of filler, which is the aggregate with particle diameter of less than 0.075 mm. Large amounts of filler change the rheological behaviour and limit the possibility of movement for the bitumen, which is blocked by the filler particles. This study evaluated the behaviour of asphalt mastics (bitumen plus filler) in the linear viscoelastic region, mixing various types of binder with different fillers. Bitumens produced in Italy with penetration 50-70 and 70-100 0.1xmm were used. The fillers were selected in order to represent two types of material, a common construction product (cement) and a conventional by-product often processed as a waste (municipal solid waste incinerator ash). The amount of filler added to the bitumen varied from 0 to 100% by weight of bitumen. Tests were performed using a dynamic shear rheometer with two geometries, in amplitude and frequency sweep, with temperature scales between 15 °C and 70 °C. The tests verified that with a high filler content (100% by weight) the behaviour of mastic changes radically, due to the reduction of mobility and higher viscosity induced by the filler. The SHRP-derived Christensen-Anderson model, which can be conventionally used for describing the behaviour of mastics with a low percentage of filler, is not suitable for mastics with the characteristics analysed.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3212627
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