8. Asphalt concrete bindings effect

An important structure unit of asphalt concrete that is asphalt concrete binding is generated while mixing mineral filler with organic binding. The nature of asphalt concrete is determined by the quality of the asphalt concrete binding. The properties of the system "bitumen-mineral powder" depend on the properties of binding, chemical-mineral composition and mineral filler dispersion, and also these components proportions [18].

The interaction of bitumen with mineral powder is conditioned not only by the rather developed specific filler surface but also by internal grain surface generated by the branched microspores system. Porous fine dispersed fillers cause strong structuralized influence than dense ones. Micropores differ by the high adsorption potential due to which the significant part of surface active components of bitumen sorbs in them. Therefore, it is possible to suggest that porous mineral fillers will cause strong structuralized influence on bitumen than the traditional materials. It is clear that the interest to porous fillers in asphalt concrete composition is conditioned by this.

Mineral powder from shungite (Medvezhjegorskoe deposit) differs from the traditional one from dolomite by bigger porosity of the surface and high developed micropores system and also bitumen of the grade БНД 60/90 of Ryazan НПЗ was investigated. The dispersed raw under study will be correct to test for accordance with the demands [5] asphalt concrete mixes mineral powders. Characteristics of under research fillers properties are shown in Table 5.

Mineral powder meets the requirements. But the porosity of the material 20–25% higher than the porosity of lime stone filler and the value of specific surface at the same grain metric proportion is 60–70% higher. So the conclusion is the system of micropores of under research carbon containing raw material is more developed.

The results of the experimental researches of asphalt concrete binding agent. From our point the most informative method of studying the method "bitumen-mineral powder" is the investigation of asphalt concrete binding agent characterized by greater homogeneity of the structure and stability of the properties. Asphalt concrete binding agent was produced from according to the standard method with the before bitumen amount batching. Thus for the mineral powder from shungite the index is 16.2% which is 26% more than traditional lime stone mineral powder has. These data are correlated with the indexes of bitumen proportion in powders. The research results of the physical chemical properties of asphalt concrete binding agent with optimal amount of bitumen are given in Table 6.

Coefficient of composite thermal stability and its water resistance are the most interesting among all the data. Therefore, the index of heat resistance of shungite is 14.3% more than while using the traditional mineral powder from lime stone or dolomite. Thermal resistance of mixes and asphalt concrete is characterized by the coefficient of thermal resistance defined as the ratio of ultimate compression strength at t-20C to the ultimate stress limit at t = 50C.

As the under research, raw material is porous; the water can penetrate inside the shungite grains and decompose the asphalt concrete binding agent on the bitumen- mineral powder interface if binding agent covers mineral powder surface partially or if the adhesion bonds are weak.


Table 5. Characteristics of under research illers properties.

The assessment of asphalt concrete by the method of dynamic effect on the water saturated samples is more corresponding to the operation conditions of the material in road construction than the known methods based on statistic water action. That is why the tests of comparison fatigue of asphalt concrete durability were conducted on dry and water saturated samples. Water saturation of asphalt concrete samples was 1.65–1.66% by volume. Values of fatigue

Number of destruction cycles

Without heating 14,756 10,416 After 5 h of heating 17,707 11,488

Without heating 17,757 14,322 After 5 h of heating 20,092 16,297

dry Water saturated

The application of shungite material instead of the lime stone mineral powder promotes the growth of asphalt concrete fatigue durability especially in the conditions of water saturation. It connects with high adhesion activity of shungite carbon with shungite carbon containing material [21].

The increase of asphalt concrete fatigue durability with the application of shungite mineral powder as a result of aging (after the heating for 5 h) demonstrates the properties stability under temperature effect. It is clear that it connects with oil migration from pores in carbon

An important structure unit of asphalt concrete that is asphalt concrete binding is generated while mixing mineral filler with organic binding. The nature of asphalt concrete is determined by the quality of the asphalt concrete binding. The properties of the system "bitumen-mineral powder" depend on the properties of binding, chemical-mineral composition and mineral

The interaction of bitumen with mineral powder is conditioned not only by the rather developed specific filler surface but also by internal grain surface generated by the branched microspores system. Porous fine dispersed fillers cause strong structuralized influence than dense ones. Micropores differ by the high adsorption potential due to which the significant part of surface active components of bitumen sorbs in them. Therefore, it is possible to suggest that porous mineral fillers will cause strong structuralized influence on bitumen than the traditional materials. It is clear that the interest to porous fillers in asphalt concrete composi-

durability of asphalt concrete samples were given in Table 4.

Table 4. Values of fatigue durability of asphalt concrete samples.

(Thermal effect)

containing materials and bitumen film rejuvenation during aging.

filler dispersion, and also these components proportions [18].

8. Asphalt concrete bindings effect

Asphalt concrete composition Aging

Granit sieving – 92%,

Granit sieving –92%, shungite mineral powder – 8%, road oil asphalt 60/90–7,

mineral powder 8%, bitumen of road oil asphalt 60/90–7.5%

lime-stone

102 Modified Asphalt

tion is conditioned by this.


2. The results of investigation of shungite mineral powder on scan prob. microscope with nanodementional resolution demonstrate the ability of shungite with high adsorption activity in comparison with organic binding promotes its structurization. Together with bitumen it forms the structured dispersed system acting as a binding material in

The Enhancement of Asphalt Concrete Surface Rigidity Based on Application of Shungite-Bitumen Binder

http://dx.doi.org/10.5772/intechopen.76877

105

3. It is determined that at the result of shungite mineral powder application asphalt concrete has better water resistance and long water saturation properties which provides high corrosion resistance of asphalt concrete carpet in comparison with traditional powder

SiO2 Аl2О<sup>3</sup> Fе2О<sup>3</sup> Fе2О<sup>3</sup>

1 (shungite) 45.5 2.3 1.9 1.0 2 (lime stone) 2.1 0.1 1.2 0.8

Figure 15. Microstructure of asphalt concrete binding agent from a) shungite b) from lime stone.

Table 7. Chemical composition of mineral powders from shungite and lime stone.

concrete.

from lime stone rock.

Sample Mass portion, %

Table 6. Physical chemical properties of asphalt binding agent.
