Effect of ageing process on fungiform papillae density

Abstract

In the last few decades, highway agencies and the paving companies have invested huge efforts on increasing the amount of reclaimed asphalt (RA) to be introduced in the production of new asphalt concrete (AC). This technique, so-called hot recycling of RA, offers several economical and environmental advantages tightly related to the replacing of natural materials, such as aggregates and bitumen, with recycled one. Indeed, the hot recycling of RA implies a reduction of the virgin aggregate and bitumen supply to produce AC. Additionally, hot recycling allows decreasing the amount of RA disposal. However, when a high amount of RA is hot recycled, the mechanical properties of aged bitumen must be considered for an appropriate mix design. In this case, recycling additives are used to achieve good mechanical performance. This paper deals with the effect of ageing and of a specific rejuvenator on mechanical properties of a paving grade bitumen. Moreover, the effect of ageing on mechanical properties of the rejuvenated bitumen is investigated. The results showed that the stiffening effect of ageing can be reduced or restored by the use of the rejuvenator. In addition, the ageing process affects the rejuvenated bitumen as well as it does for paving grade bitumen.