Regenerating

2 posts

POLYGEN

Milling regenerating

Regenerating for the use of high percentages of milled material for the preparation of hot mixes and warm conglomerates

After laying, asphalt begins an aging process that drastically changes its characteristics and makes it extremely difficult to reuse it in the new conglomerates. During the aging process, the relationship between asphaltenes and maltenes changes, leading to greater bitumen rigidity and viscosity and a decrease in ductility. However, the increase in the number of asphaltenes is not the only reason for aging. Asphaltenes interact with each other and / or with malteni, the increase in viscosity also depends very much on the shape of the asphaltenes particles. Most of the bitumen aging occurs during mixing with aggregates, transport and laying processes due to exposure to high temperatures. This is referred to as short-term aging and is caused by:
■ oxidation that occurs during the mixing phases during the preparation of the conglomerates;
■ loss of volatile fractions (volatilization)
■ absorption of oily constituents, resins and asphaltenes by aggregates.
The amount of aging in service depends largely on the content of voids in the pavement and the depth of recovery of the milled (the surface of the road hardens faster). Long-term aging mechanisms have been recognized as:
■ oxidation due to the constant supply of fresh air;
■ polymerization;
■ photo-oxidation for surface layers;
■ syneresis due to the exudation of oily components