EFFECT OF ROAD BITUMEN MODIFICATION WITH NANOCARBON POWDER

Аннотация

Low temperature characteristics (stiffness and m-value) have been determined on a bending beam
rheometer in the paper for a road bitumen of grade BND 70/100 and the same bitumen with adding of a nanocarbon
powder in the quantity of 2% by weight. The bitumen has been produced by Pavlodar petrochemical plant
(Kazakhstan) from a crude oil of Western Siberia (Russia) by direct oxidation. The bitumen has the following
standard characteristics: penetration depth of the needle (penetration) at 25°С: 75 dmm; ductility at 25°С: 118 cm;
softening point: 47.5°С; Fraas point: -28.5°С. The nanocarbon powder with sizes of 150-200 nm has been obtained
from a coal of the “Saryadyr” deposit (Akmola region, Kazakhstan). A mechanical dispergator has been used for
dispersing of the coal with sizes up to 50 mm (till 2-3 mm), an aerodynamic mill (till 20 µm) and a reactor with
rotating electromagnetic field. Content of carbon and ash in the nanopowder is 92.74% and 2.16% respectively.
Average moisture of the nanopowder is 2%. Before testing on the bending beam rheometer the neat bitumen and the
nanocarbon bitumen have passed double artificial aging: short-term aging under standard AASHTO T 240-13 and
long-term aging under standard ASTM D 6521-08 [14]. It is found out that addition of the nanocarbon powder
improves low temperature resistance of the bitumen. The effect of the bitumen modification with the nanocarbon
powder is the highest one at very low temperatures. The possibility has been shown for the use of the bitumen of
grade BND 70/100 (of more viscous consistence) at its modification with the nanopowder both in the southern
regions of the republic and in the northern ones.