3. Comparison of reactive ability of shungite and lime stone powders during amalgamation with bitumen

Mineral powder together with bitumen form oriented bitumen layers on mineral grains. These oriented bitumen layers are developed in different degrees. These layers are followed by free bitumen. The qualitative structure of bitumen changes occur in oriented layer as a result of the adsorption processes and bitumen or its separate components diffusion deep into mineral material.

Adsorption is the concentration of substances on a surface or inside a solid body. Not less than two components take part in the process of adsorption.

The nature of such interaction is conditioned not only by the group bitumen structure but also by the properties of mineral powder, its chemical mineralogical composition, grains form, structural peculiarities and surface nature.

Active surface centers are on the surfaces of any mineral material. They condition their capacity of reaction and take part in the interaction with organic binding agent.

The presence of the active centers which can absorb practically all organic compounds existing in bitumen provides strong adhesion contacts between binding agents and mineral materials surface.

Chemisorptions are substances adsorption from the surrounding environment by liquid or solid body. It is accompanied by the formation of chemical linkages. Absorption is considered as a substance chemical adsorption by solid body surface that is as chemical adsorption. At chemisorptions there is a linkage formed between atoms (molecules) of adsorbent and adsorbate. Therefore, it can be considered as chemical reaction which is limited by surface layer.

Interaction of binding agents and mineral materials is the most fully appeared during chemisorptions processes taking place on the interface. Herewith the binding components diffuse into pores spaces of mineral materials and there is a physical adsorption of binding surface film which adheres to the stone materials.

In the very work, the reactive properties of the mineral material were considered according to the bitumen amount adsorbed from benzene solutions [9].

The amount of bitumen adsorption from benzene solutions on the surface of mineral powders was defined by the following method:

Bitumen solutions were prepared on the pure chemical nonpolar benzene of four different concentrations: 1, 3, 6, 9 g/l. Weights of tested powders of 5 g each were put into with groundin stoppers glass flasks of 200 ml capacity and then they were covered with 50 cm<sup>3</sup> of benzene solutions of designed concentrations and agitated on a special plant for an hour.

After agitating, the flasks with the contents were left alone for 24 h. Then the part of the solution was taken out from the flasks and the bitumen concentration was determined by photometer KFK-3 (КФК-3).

The absorption was calculated by the formula:

$$\mathbf{A} = \frac{(\mathbf{C}\_o - \mathbf{C}) \cdot \mathbf{V}}{1000 \cdot \mathbf{m}} \tag{1}$$

where

Thus the maximal degree of roughness of asphalt concrete binding agent with shungite is 0.027μm (the scan size is 5.0 5.0 μm). Fractal dimensionality of the surface is D = 1.64.

The less surface roughness the nearer the value of surface fractal dimensionality to the criteria "2" that is the material is more dense and homogeneous. Composite "bitumen-lime stone"

Correlation of the indicators of the surface roughness and fractal dimensionality characteristics

Mineral powder together with bitumen form oriented bitumen layers on mineral grains. These oriented bitumen layers are developed in different degrees. These layers are followed by free bitumen. The qualitative structure of bitumen changes occur in oriented layer as a result of the adsorption processes and bitumen or its separate components diffusion deep into mineral

Adsorption is the concentration of substances on a surface or inside a solid body. Not less than

The nature of such interaction is conditioned not only by the group bitumen structure but also by the properties of mineral powder, its chemical mineralogical composition, grains form,

3. Comparison of reactive ability of shungite and lime stone powders

Composite "bitumen-shungite" surface in 3D is presented in Figure 5.

Figure 7. Correlation of the surface roughness and fractal dimensionality characteristics.

surface in 3D is given in Figure 6.

during amalgamation with bitumen

two components take part in the process of adsorption.

structural peculiarities and surface nature.

is shown in Figure 7.

88 Modified Asphalt

material.

Со – initial concentration, kg/m<sup>3</sup> ;

С – equilibrium concentration, kg/m<sup>3</sup> ;

V – solution volume, m<sup>3</sup> ;

M – mineral powder mass, kg

The amount of bitumen chemically connected with the powder surface was defined according to the difference of adsorption and adsorbed bitumen values.

Desorption were conducted by the following method:

The powder left after measuring of adsorption value was covered by 50 sm3 of pure benzene and agitated on a special plant for an hour. The flasks were left alone for 24 h. After that the samples were taken and the bitumen concentration was determined by photometer KFK-3 (КФК-3).

The bigger amount of bitumen is adsorbed on the shungite mineral powder surface than on the lime stone material surface. It was the same at the primary absorption and after the adsorption with benzene. For example, 19 g/g of bitumen are absorbed on shungite surface at bitumen concentration in benzene solution of 3 g/g but 14 g/g of bitumen are absorbed on a lime stone

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

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

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The influence of mineral powders on the bitumen structure changing after its desorption from the surface was researched by the spectroscopy method. This method allows investigating mechanism of powders interaction with bitumen, revealing the changes in its structure after

It was determined that after bitumen desorption from the shungite surface insignificant amount of organic compounds were left in binding agent. Therefore, they were adsorbed on the surface of shungite mineral powder while their great part on the surface of mineral powder from lime stone was desorbed with benzene. Figure 8 demonstrate adsorption–desorption of

The research results of bitumen adsorption and desorption on the surfaces of dispersed materials and bitumen infrared spectrums after the contact with mineral powders show that shungite mineral powder interacts with bitumen more actively than with the lime stone powder (Figure 8). The obtained results prove the formation of stable chemisorption bitumen

During infrared radiation passing through the substance, the excitation of molecule oscillating movement or their separate fragments takes place. It is observed that the abatement of intensity of the light passed through the sample. The absorption is not in the whole spectrum of incident radiation but only at those wavelengths the energy of which relative to the energy of excitation of oscillations in the molecules under research. Therefore, the wavelengths (or frequency) at which there is maximal absorption of infrared radiation can indicate the presence

of these or those functional groups or other fragments in the sample molecular.

particles surface state, studied with the microscope (C3M) NanoEducator.

5. Shungite mineral powder effect on the asphalt concrete structural-

The researchers studied theoretical and practical aspects of shungite mineral powder with account of its interaction with organic binding. The interaction of binding agent with mineral materials depends on chemisorptions processes on their interface. The strength of chemiadsorption bonds between bitumen and mineral powder depends not only on the chemical impact of the bitumen and mineral powder components but also on the mineral powder

surface, respectively.

adsorption on the mineral powder surface.

bonds with shungite surface.

4. Infrared spectroscopy

mechanical properties in time

bitumen on shungite and lime stone surfaces on benzene solutions.

According to the amount of the powder left on the mineral powder surface, it is possible to reason about the powder surface activity.

The conducted experiment allows to estimate the adsorption properties of the under test mineral materials. The results of the investigations are given in the Figure 8.

Figure 8. Adsorption–desorption of bitumen on shungite and lime stone surfaces on benzene solutions.

The bigger amount of bitumen is adsorbed on the shungite mineral powder surface than on the lime stone material surface. It was the same at the primary absorption and after the adsorption with benzene. For example, 19 g/g of bitumen are absorbed on shungite surface at bitumen concentration in benzene solution of 3 g/g but 14 g/g of bitumen are absorbed on a lime stone surface, respectively.

The influence of mineral powders on the bitumen structure changing after its desorption from the surface was researched by the spectroscopy method. This method allows investigating mechanism of powders interaction with bitumen, revealing the changes in its structure after adsorption on the mineral powder surface.

It was determined that after bitumen desorption from the shungite surface insignificant amount of organic compounds were left in binding agent. Therefore, they were adsorbed on the surface of shungite mineral powder while their great part on the surface of mineral powder from lime stone was desorbed with benzene. Figure 8 demonstrate adsorption–desorption of bitumen on shungite and lime stone surfaces on benzene solutions.

The research results of bitumen adsorption and desorption on the surfaces of dispersed materials and bitumen infrared spectrums after the contact with mineral powders show that shungite mineral powder interacts with bitumen more actively than with the lime stone powder (Figure 8). The obtained results prove the formation of stable chemisorption bitumen bonds with shungite surface.
