LT6536B - Crumb rubber modified bitumen - Google Patents

Abstract

This invention relates to the field of bitumen compositions, more precisely to modified bitumen, used in the production of asphalt mixtures suitable for the installation of roads and other traffic areas coatings with increased durability and resistance to high environmental impact factors. The purpose of the invention is to produce crumb rubber modified bitumen characterized by rut resistance, durability, resistance to environmental impact and a relatively low cost. The modified bitumen composition comprising bitumen and crumb rubber while the modified road bitumen is 50/70, crumb rubber particle size is less than 1.0 mm, when the weight (%) ratio of the components is: bitumen - 94 - 96; crumb rubber - 4 - 6.

Description

BACKGROUND OF THE INVENTION The present invention relates to the field of bituminous material compositions, more specifically modified bitumen used in the manufacture of asphalt mixtures for use in the application of high resistance to environmental factors and durability in road and other traffic area applications.

Used rubber flour modified bitumen containing 50/70 unmodified bitumen and 10% used tire rubber flour is known. The penetration of this bitumen is 43 mm ' ¹ and the softening point is 57 ° C (see Lukasz Skotnicki, Henryk Koba, Antoni Szydlo. Rubber modified stone matrix asphalts Asphalt-rubber 2012 Conference, 2012: 5). This bitumen is characterized by insufficient rigidity. The viscosity of this bitumen and its resistance to frost are also underestimated.

The nearest modified bitumen consists of basic bitumen and used rubber flour for tires. The basic modifiable bitumen is 60/70 and the used tire flour is up to 2.0 mm in size. The weight percent of the known modified bitumen composition is: base bitumen 92, used tire flour 8 (see Daryoush Yousefi Kebria, Rohalah Moafimadani, Yaser Goli). Materials and Pavement Design 16, 2015: 949).

The prototype has a softening temperature of 57.4 ° C and a penetration of 48 mm ' ¹ . However, there is no data on the viscosity of bitumen - based on the literature review it can be stated that with more than 7% of the used tire rubber flour, bitumen is viscous which causes problems in pumping bitumen through pipes, asphalt mixtures and asphalt layers. Neither is the result of frost resistance - frost-resistant bitumen shrinks in winter, which determines the formation of asphalt pavement transverse cracks. The prototype is not rigid enough.

The object of the invention is to provide bitumen modified rubber flour of used tires with rutting resistance, durability, environmental resistance and relatively low cost.

This object is achieved by the fact that the modified bitumen composition comprising bitumen utilizes rubber flour of tires, and the modified bitumen is 50/70 grade, the particles of used rubber flour being less than 1.0 mm, with a component ratio by weight: bitumen of 94 96;

used tire flour - 4 - 6.

The objective is also achieved by modifying the bitumen at 170-200 ° C.

The modified bitumen composition of the present invention utilizes extremely fine rubber flour from used tires, which allows for more efficient bitumen modification. In addition, the optimum amount of component components found allows for good rutting resistance. Also, the composition of the invention has a relatively low cost due to the use of local used tire flour and local bitumen.

The optimum amounts of components included in the rubber flour modified bitumen of used tires have been determined by experimental studies.

The rubber flour modified bitumen composition of the used tires according to the invention is illustrated by examples.

an example of bitumen modified with used rubber flour for tires

Used rubber flour modified bitumen consists of basic unmodified bitumen (eg "50/70") and used tire rubber flour (eg fr. 0.063 / 0.6 mm).

The percentage by weight of bitumen modified bitumen modified tires shall be as follows:

bitumen - 96;

used tire flour - 4.

an example of bitumen modified with used rubber flour for tires

Used flour modified bitumen for used tires consists of basic unmodified bitumen (eg "50/70") and used tire flour (eg fr. 0.063 / 0.6 mm).

The percentage by weight of bitumen modified bitumen modified tires shall be as follows:

bitumen - 95;

used tire flour - 5.

The properties of used rubber flour modified bitumen tires are shown in the following tables: Table 1 shows 1 sample of used rubber flour modified tires, Table 2 shows 2 samples of used rubber flour modified tires and the testing standards are given in Table 3.

table

Feature Set value Bitumen penetration, mm ' ¹ 34.7 Bitumen softening point, ° C 62.4 Viscosity of bitumen at 135 ° C, Pa * s 1.4 Bitumen critical low temperature, ° C -30.4

table

Feature Set value Bitumen penetration, mm ' ¹ 35.1 Bitumen softening point, ° C 63.1 Viscosity of bitumen at 135 ° C, Pa * s 1.5 Bitumen critical low temperature, ° C -31.0

table

The test Standard Bitumen penetration, mm ' ¹ BS EN 1426 Bitumen softening point, ° C BS EN 1427 Viscosity of bitumen at 135 ° C, Pa * s BS EN 13302 Bitumen Critical Low Temperature, ”C BS EN 14771

The bitumen modified rubber flour of used tires has good technology, rutting resistance and low temperature effects. In addition, expensive bitumen polymers are commonly used for conventional bitumen modification, so the use of used rubber flour in tires instead of polymers would significantly reduce the price of bitumen.

The developed bitumen modified bitumen of used tires can be used for the production of asphalt mixtures for use on road, road and other pavement structures.

Claims (2)

DEFINITION OF INVENTION 1. Modified bitumen composition comprising bitumen and used tire flour having a modified bitumen content of 50/70 grade, used tire flour having a particle size of less than 1.0 mm, with a component ratio by weight of: bitumen - 94 - 96; used tire flour - 4 - 6. 2. A method of modifying the composition of claim 1, wherein the bitumen is modified at 170-200 ° C.