5. Shungite mineral powder effect on the asphalt concrete structuralmechanical properties in time

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

The higher shungite mineral powder porosity than limestone promotes the concentration of the considerable amount of resin in surface microspores. But some amount of oils penetrates the material because of the selective diffusion. That is why structured bitumen films on the shungite particles surface have strong cohesion with them.

Porous filler in shungite bitumen binding agent composition provides the lower temperature of the surface cracking. The tensile strength in such a composition is rather higher than the standard asphalt concrete tensile strength based on dense filler as the friction between the particles is higher due to the greater roughness and specific surface of shungite particles.

The presence of shungite bitumen binding agent in asphalt concrete mix allows increasing surface fracture strength. It is because the chemical activity of shungite particles after their pores filled with bitumen light fractions minimizes internal tension and improves thermal stability of the material.

Shungite particle porosity has better developed specific surface of different mix components as during dry mixing of mineral materials before their integration with bitumen the small mineral powder particles adhere to filler grains. At such processing, a mechanical "modification" of big grains surface which improve bitumen adhesion takes place with them.

shear strength of asphalt concrete surfaces with shungite bitumen binding agent [4]. It has become usual that the asphalt concrete life service is considerably smaller than theoretically possible according to the abradability conditions. It shows the unconformity of structure – rheological performances of asphalt concrete and its operation conditions. Asphalt concrete during its life duration is affected by different factors: traffic loads, heating, cooling, humidification, and so on. But the normative documents recommend asphalt concrete designing only according to the strength in dependence on traffic load. The possibility of forming shear deformations on asphalt concrete surface in summer time or thermal cracks at negative temperatures is not considered. That is why the deformations excite premature surface destruc-

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Figure 10. Сhanging of asphalt concrete structural mechanical properties in time at t + 50C.

Asphalt concrete under different effects is elastic or elastic-viscous, or plastic substance. The theory of elasticity or the theory of plasticity describes only particular cases of asphalt concrete stress state and cannot create the full picture of asphalt concrete operation. Rheology describes

In rheology, the possibility to describe the stress and deformation in time by differential equations appears. The sphere of these equations definition depends on conditions in which the given materials work. It is suggested that compositional viscous -elastic–plastic material

While differential equating the main material properties are shown as physically substantiated mechanical models, deformation laws of which are premeditated. In rheology, different simple and complicated models of physical bodies which should correspond to the differential equa-

While researching rheological characteristics of asphalt concrete based on mineral powders from shungite and limestone, the method by Boguslavsky [10] and Ya. N. Kovalyov was applied. For that target, the height h and the diameter d of asphalt concrete samples before

According to these data, the values of rheological parameters were calculated as follows:

tions more often than the vehicle loads.

tions situation are used.

asphalt concrete work in deflected mode more objectively.

has the total main properties: elasticity, viscosity and plasticity.

and after the testing and the limit of compression strength were measured.

Bitumen in thin layer on the mineral particles surface becomes structured, more dense and viscous changing its nature in time. That is why the nature of asphalt concrete mixes based on mineral powder from shungite was defined in different periods at samples conditioning in air: 2, 15, 30, 60 and 90 daily age. Changing of structural mechanical properties of asphalt concrete in time at t + 20C is presented in Figure 9.

The analysis of received results allows determining the following:

in consequence of continuing processes of structure forming the compression strength limits of asphalt concrete based on shungite binding agent at t = 20 (Figure 9) and 50C (Figure 10) increases in dependence on sample age conditioning in air. Figure 10 shows the changing of asphalt concrete structural mechanical properties in time at t + 50C.

The higher strength limit of asphalt concrete with mineral powder under compression at t = 20 and 50C than standard asphalt concrete based on lime mineral powder indicates the higher

Figure 9. Changing of structural mechanical properties of asphalt concrete in time at t + 20C.

The Enhancement of Asphalt Concrete Surface Rigidity Based on Application of Shungite-Bitumen Binder http://dx.doi.org/10.5772/intechopen.76877 93

Figure 10. Сhanging of asphalt concrete structural mechanical properties in time at t + 50C.

The higher shungite mineral powder porosity than limestone promotes the concentration of the considerable amount of resin in surface microspores. But some amount of oils penetrates the material because of the selective diffusion. That is why structured bitumen films on the

Porous filler in shungite bitumen binding agent composition provides the lower temperature of the surface cracking. The tensile strength in such a composition is rather higher than the standard asphalt concrete tensile strength based on dense filler as the friction between the particles is higher due to the greater roughness and specific surface of shungite particles.

The presence of shungite bitumen binding agent in asphalt concrete mix allows increasing surface fracture strength. It is because the chemical activity of shungite particles after their pores filled with bitumen light fractions minimizes internal tension and improves thermal

Shungite particle porosity has better developed specific surface of different mix components as during dry mixing of mineral materials before their integration with bitumen the small mineral powder particles adhere to filler grains. At such processing, a mechanical "modification" of big

Bitumen in thin layer on the mineral particles surface becomes structured, more dense and viscous changing its nature in time. That is why the nature of asphalt concrete mixes based on mineral powder from shungite was defined in different periods at samples conditioning in air: 2, 15, 30, 60 and 90 daily age. Changing of structural mechanical properties of asphalt concrete

in consequence of continuing processes of structure forming the compression strength limits of asphalt concrete based on shungite binding agent at t = 20 (Figure 9) and 50C (Figure 10) increases in dependence on sample age conditioning in air. Figure 10 shows the changing of

The higher strength limit of asphalt concrete with mineral powder under compression at t = 20 and 50C than standard asphalt concrete based on lime mineral powder indicates the higher

grains surface which improve bitumen adhesion takes place with them.

The analysis of received results allows determining the following:

asphalt concrete structural mechanical properties in time at t + 50C.

Figure 9. Changing of structural mechanical properties of asphalt concrete in time at t + 20C.

shungite particles surface have strong cohesion with them.

stability of the material.

92 Modified Asphalt

in time at t + 20C is presented in Figure 9.

shear strength of asphalt concrete surfaces with shungite bitumen binding agent [4]. It has become usual that the asphalt concrete life service is considerably smaller than theoretically possible according to the abradability conditions. It shows the unconformity of structure – rheological performances of asphalt concrete and its operation conditions. Asphalt concrete during its life duration is affected by different factors: traffic loads, heating, cooling, humidification, and so on. But the normative documents recommend asphalt concrete designing only according to the strength in dependence on traffic load. The possibility of forming shear deformations on asphalt concrete surface in summer time or thermal cracks at negative temperatures is not considered. That is why the deformations excite premature surface destructions more often than the vehicle loads.

Asphalt concrete under different effects is elastic or elastic-viscous, or plastic substance. The theory of elasticity or the theory of plasticity describes only particular cases of asphalt concrete stress state and cannot create the full picture of asphalt concrete operation. Rheology describes asphalt concrete work in deflected mode more objectively.

In rheology, the possibility to describe the stress and deformation in time by differential equations appears. The sphere of these equations definition depends on conditions in which the given materials work. It is suggested that compositional viscous -elastic–plastic material has the total main properties: elasticity, viscosity and plasticity.

While differential equating the main material properties are shown as physically substantiated mechanical models, deformation laws of which are premeditated. In rheology, different simple and complicated models of physical bodies which should correspond to the differential equations situation are used.

While researching rheological characteristics of asphalt concrete based on mineral powders from shungite and limestone, the method by Boguslavsky [10] and Ya. N. Kovalyov was applied. For that target, the height h and the diameter d of asphalt concrete samples before and after the testing and the limit of compression strength were measured.

According to these data, the values of rheological parameters were calculated as follows:

Relaxation time:

$$
\Theta = \frac{400 \cdot h \cdot \Delta h^2}{\Delta d^2} \tag{2}
$$

For optimization of composition of crushed stone-mastic and shungite mineral powder, the

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

specific peculiarities of them were considered.

Figure 11. Grain proportion of mineral part of asphalt concrete.

Place of sampling Layer thickness g(upper /lower) layer)

Fact. Weight of

1 2 3 4 5 6 9 10

Surface samples

> Weight of dry sample in 30 minutes of aging

Volume weight g/cm<sup>3</sup>

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95

Water saturation, % of volume

in water, g

dry sample, g

1 1–1 (В) 5.0 572.20 576.93 2.53 2.36

3 3–1 (В) 5.3 967.88 970.26 2.57 1.68

4 4–1 (В) 5.0 902.55 905.24 2.58 1.01

5 5–1 (В) 5.1 868.72 871.10 2.59 1.66

6 6–1 (В) 5.2 909.79 911.48 2.60 1.28

Table 2. Physical-mechanical indexes of asphalt-concrete from pilot and control sites.

1–2 (В) 5.1 920.72 927.76 2.54 3.50 1–3 (В) 5.0 972.90 976.12 2.58 2.11

3–2 (В) 5.8 973.60 976.79 2.57 1.26 3–3 (В) 5.5 1169.82 1171.60 2.56 0.66

4–2 (В) 5.3 1041.18 1044.03 2.54 1.88 4–3 (В) 5.1 879.19 884.64 2.54 3.10

5–2 (В) 5.0 1152.31 1156.71 2.50 2.46 5–3 (В) 5.0 871.29 872.98 2.56 1.79

6–2 (В) 5.7 1420.38 1422.85 2.56 0.81 6–3 (В) 5.7 1363.83 1366.46 2.55 1.06

Date of testing Number

01.10.2011 (shungite mineral (powder)

01.10.2011 Lime stone mineral powder

of samples

Retardation time:

$$
\tau = \frac{1000 \cdot \Delta d}{h} \tag{3}
$$

Coefficient of elasticity:

$$K = \frac{R \cdot h}{\Delta h} \tag{4}$$

Viscose compliance coefficient:

$$
\gamma = \frac{\pi}{K} \tag{5}
$$

Viscose coefficient according to Mazwell' s equation:

$$
\eta\_m = \Theta \cdot K \tag{6}
$$

Viscosity of undisturbed structure was defined by the formula.

$$\eta\_m = \frac{400 \cdot R \cdot h\_1^2 \cdot \Delta h}{\Delta d} \tag{7}$$

Water saturation duration, samples age and freezing cycle number influence rheological characteristics of asphalt concrete were investigated in the road laboratory.

The blanket from crushed stone-mastic mix with shungite mineral powder was constructed in order to satisfy the experiment and study physical-mechanical properties in real operation conditions. Before that, shungite mineral powder of gabbroic-diabase- crushed stone and crushed stone from gabbroic –diabase and bitumen were tested.

The additive based on cellulose filaments Viapor was used as stabilized additive preventing mix segregation and bitumen-shungite binding delimitation at high technologic temperatures. This additive increases the thickness of bitumen film on mineral particles. The mineral proportion of crushed stone-mastic asphalt concrete mix was matched during the research. The composition should provide as follows:


For optimization of composition of crushed stone-mastic and shungite mineral powder, the specific peculiarities of them were considered.

Figure 11. Grain proportion of mineral part of asphalt concrete.

Relaxation time:

94 Modified Asphalt

Retardation time:

Coefficient of elasticity:

Viscose compliance coefficient:

Viscose coefficient according to Mazwell' s equation:

Viscosity of undisturbed structure was defined by the formula.

acteristics of asphalt concrete were investigated in the road laboratory.

crushed stone from gabbroic –diabase and bitumen were tested.

• shear resistance and rut forming resistance at high temperatures;

• water saturation of surface layers at small residual porosity.

• uneven surface texture and designed coefficient of adhesion;

composition should provide as follows:

• high wear resistance.

• aging resistance.

<sup>Θ</sup> <sup>¼</sup> <sup>400</sup> � <sup>h</sup> � <sup>Δ</sup>h<sup>2</sup>

<sup>τ</sup> <sup>¼</sup> <sup>1000</sup> � <sup>Δ</sup><sup>d</sup>

<sup>K</sup> <sup>¼</sup> <sup>R</sup> � <sup>h</sup>

<sup>γ</sup> <sup>¼</sup> <sup>τ</sup>

<sup>η</sup><sup>m</sup> <sup>¼</sup> <sup>400</sup> � <sup>R</sup> � <sup>h</sup><sup>2</sup>

Water saturation duration, samples age and freezing cycle number influence rheological char-

The blanket from crushed stone-mastic mix with shungite mineral powder was constructed in order to satisfy the experiment and study physical-mechanical properties in real operation conditions. Before that, shungite mineral powder of gabbroic-diabase- crushed stone and

The additive based on cellulose filaments Viapor was used as stabilized additive preventing mix segregation and bitumen-shungite binding delimitation at high technologic temperatures. This additive increases the thickness of bitumen film on mineral particles. The mineral proportion of crushed stone-mastic asphalt concrete mix was matched during the research. The

• higher crack resistance at surface deformation and under mechanic effects from vehicles.

<sup>1</sup> � Δh

<sup>Δ</sup>d<sup>2</sup> (2)

<sup>h</sup> (3)

<sup>Δ</sup><sup>h</sup> (4)

<sup>K</sup> (5)

<sup>Δ</sup><sup>d</sup> (7)

η<sup>m</sup> ¼ Θ � K (6)


Table 2. Physical-mechanical indexes of asphalt-concrete from pilot and control sites.


Table 3. The dynamics of adhesion capacity on pilot and control sites.

dynamics of adhesion capacity on pilot and control sites are given in Table 3, but the ruts state

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The monitoring for the state of crushed stone-mastic blanket shows that shungite containing asphalt concrete is in less degree rut prone in comparison with asphalt concrete on lime stone

The assessment and prediction of fatigue asphalt concrete properties are the actual problems in

The effect of fatigue is taken as a process of progressive material destruction by cracks. There are differed three forms of destruction: the beginning of cracks formation; the period of their

In comparison with the initial period of cracks formation which takes a significant time, the phase of stable cracks growth can be analyzed as the main fatigue process. Cyclic effect of moving vehicles (load) leads to the progressive cracks growing up to the critical depth. A crack increases spontaneously in the third stage which induces the fracture of the material. [11].

The analysis of fatigue performances based on the thermal fluctuation theory of fracture by S.N. Zhurkov shows that fatigue properties of asphalt concrete directly depends on the degree of the plasticity and there is a definite connection between strength and fatigue material properties. There are two different methods of fatigue tests [12]: the test with constant stress

6. The analysis of traffic load effect on a road blanket

assurance of nonrigid road surface reliability.

Figure 13. Ruts state on the site with shungite mineral power.

stable growth and the stage of their intensive growth.

amplitude; the test with constant deformation amplitude.

is demonstrated in Figure 13.

mineral powder.

Figure 12. The diagram of sampling on pilot site.

The materials physical-mechanic properties which comply with demands of standard documents were used in asphalt concrete crushed stone-mastic composition.

Granularmetric proportion of crushed-stone asphalt-concrete is demonstrated in Figure 11.

After asphalt concrete paving on the pilot site, the blanket has been observed. The adhesion coefficient, evenness, rutting and physical-mechanical properties of asphalt concrete was defined. The results of physical-mechanical properties, adhesion indexes testing are in Tables 2, 3, and the diagram of sampling is in Figure 12. Physical-mechanical indexes of asphalt-concrete from pilot and control sites are in Table 2.

There is the diagram of sampling on pilot site demonstrated in Figure 12.

The coefficient of adhesion is defined at the same time on the pilot site of crushed stone surface with shungite mineral powder and on the control site with lime stone mineral powder. The The Enhancement of Asphalt Concrete Surface Rigidity Based on Application of Shungite-Bitumen Binder http://dx.doi.org/10.5772/intechopen.76877 97

Figure 13. Ruts state on the site with shungite mineral power.

The materials physical-mechanic properties which comply with demands of standard docu-

stone

30.08.2011 19.10.2012 19.05.2012 03.10.2012 08.05.2013 30.08.2011 19.10.2012 19.05.2012 03.10.2012 08.05.2013

0.382 0.53 0.451 0.389 0.365 0.413 0.443 0.401 0.325 0.309 0.333 0.5 0.437 0.361 0.338 0.379 0.398 0.359 0.315 0.246 0.43 0.56 0.466 0.418 0.393 0.448 0.489 0.443 0.335 0.372

Lime stone Lime stone Lime stone Lime stone

Granularmetric proportion of crushed-stone asphalt-concrete is demonstrated in Figure 11.

After asphalt concrete paving on the pilot site, the blanket has been observed. The adhesion coefficient, evenness, rutting and physical-mechanical properties of asphalt concrete was defined. The results of physical-mechanical properties, adhesion indexes testing are in Tables 2, 3, and the diagram of sampling is in Figure 12. Physical-mechanical indexes of

The coefficient of adhesion is defined at the same time on the pilot site of crushed stone surface with shungite mineral powder and on the control site with lime stone mineral powder. The

ments were used in asphalt concrete crushed stone-mastic composition.

There is the diagram of sampling on pilot site demonstrated in Figure 12.

asphalt-concrete from pilot and control sites are in Table 2.

Figure 12. The diagram of sampling on pilot site.

Shungite Shungite Shungite Shungite Shungite Lime

96 Modified Asphalt

0.390 0.510 0.380 0.450 0.420 0.560 0.420 0.400 0.335 0.520 0.44 0.48

Table 3. The dynamics of adhesion capacity on pilot and control sites.

dynamics of adhesion capacity on pilot and control sites are given in Table 3, but the ruts state is demonstrated in Figure 13.

The monitoring for the state of crushed stone-mastic blanket shows that shungite containing asphalt concrete is in less degree rut prone in comparison with asphalt concrete on lime stone mineral powder.

### 6. The analysis of traffic load effect on a road blanket

The assessment and prediction of fatigue asphalt concrete properties are the actual problems in assurance of nonrigid road surface reliability.

The effect of fatigue is taken as a process of progressive material destruction by cracks. There are differed three forms of destruction: the beginning of cracks formation; the period of their stable growth and the stage of their intensive growth.

In comparison with the initial period of cracks formation which takes a significant time, the phase of stable cracks growth can be analyzed as the main fatigue process. Cyclic effect of moving vehicles (load) leads to the progressive cracks growing up to the critical depth. A crack increases spontaneously in the third stage which induces the fracture of the material. [11].

The analysis of fatigue performances based on the thermal fluctuation theory of fracture by S.N. Zhurkov shows that fatigue properties of asphalt concrete directly depends on the degree of the plasticity and there is a definite connection between strength and fatigue material properties. There are two different methods of fatigue tests [12]: the test with constant stress amplitude; the test with constant deformation amplitude.

The test of fatigue with constant deformation amplitude is more correct in comparison with the test with constant strain amplitude; as practically, it is not possible to determine the constant stress during the cracks growing and accordingly and the reduction of material area.

between the mineral material grains increases and the possibility of transmission as a result of

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It was proved that the mechanism of accelerated fatigue fracture of water saturated asphalt concrete during surface under cyclic dynamic loads is conditioned in certain grade by the appearance of pulse hydrodynamic pressures in water saturated pores of between grains space. Experimental researches of fatigue properties of asphalt concrete while working in the water saturated state show that the service life before the fracture in water saturated state is shorter in 1.5–2.5 times in comparison with the asphalt concrete working in dry state [11, 16]. That is why the formation of pulse hydrodynamic pressures in pores of water saturated asphalt concrete under the moving cars dynamic loads is one of the main mechanisms of

7. Previous work reports of dynamic loads on fatigue properties of asphalt

At the car speed of more than 30 km/h the surface load process at the reference point d during a small time interval can be represented as the static load F affecting on the definite blanket volume on the base under the harmonic vibrations. With account of the before mentioned assumption, the authors used the developed in the university (VGASU) method of the prediction of asphalt concrete operational properties based on the results of testing of the beams

Vibration exciter provides the production of a frequency and vibrational amplitude from 10 up to 100 Hz and from 0.1 to 5 mm respectively gradually regulated during the operation time.

wheel load application appears.

concrete

asphalt concrete fatigue in watering conditions [14].

4 4 16 (cm) on the vibration exciter (Figure 14).

The load onto the sample can change from 2 to 60 kg.

Figure 14. Vibration exciter at the moment of asphalt concrete beams testing.

Asphalt concrete fatigue fracture in the blanket takes place as a result of cracks formation in the lower tension region and their constant diffusion onto the cover blanket surface. The number of repeated loads necessary for the cracks diffusion onto layer thickness exceeds the number of cycles before the appearance of the first fatigue crack in 20 times. Therefore, the asphalt concrete durability in a blanket exceeds the number of cycles "load-unload" without intervals in which asphalt concrete sample sustains up to fracture in the laboratory in 100 [12] or 200 [13] times.

Operation ability factors of asphalt concrete reliability can be divided into two groups: external and internal.

To the external factors we can refer the environment influence of three types: mechanical, physical-climatic and chemical; to the internal: the indexes of quality, determining the asphalt concrete ability to resist the mentioned types of external one.

The typical fatigue peculiarity is the following: the load factor which is less than the destructive one leads to the progressive durability and degradation of road surface.

Bearing capacity and operation durability of asphalt concrete blanket are more completely characterized by modulus of elasticity and tensile in bending strength.

Dynamic state of road blanket depends on traffic flow concentration and composition and also on the intervals between separate cars.

Traffic loads induce both deflections and oscillations in road blanket are conditioned by momentary elasticity and elastic deflection of road constructions.

While researching bitumen water resistance and adhesion to mineral powders in a laboratory it was proved that bitumen stresses exfoliation from the mineral material surface were comparatively small [14, 15]. In real operation conditions, the additional stresses appearing at traffic movement influence on the wet blanket exceed the thermodynamic ones. Practically, water presses into a blanket in front of the moving wheel and presses out from a blanket after a wheel. The results of such a pumping action are various and difficult for consideration.

At short-term contact of moving wheels with surface, the water pressure in pores of up to 0.05 cm radius is not enough for asphalt concrete fracture but for popcorn mixes it can reach destruction quantity.

If the prolong temperatures are >50С the deformations of different types appear on an asphalt concrete blanket. The reason is the following: after heat accumulation in asphalt concrete layers, the degradation of bitumen viscosity takes place. According to the second law of thermodynamics (entropy), the grade of the temperature, concentration, barometric pressure always direct from the big value to small one. That is why bitumen starts to move upwards because its concentration is higher inside the asphalt concrete blanket than on the surface. Hereby there is its transition from structured state into the phase of free bitumen. The distance between the mineral material grains increases and the possibility of transmission as a result of wheel load application appears.

The test of fatigue with constant deformation amplitude is more correct in comparison with the test with constant strain amplitude; as practically, it is not possible to determine the constant stress during the cracks growing and accordingly and the reduction of material area. Asphalt concrete fatigue fracture in the blanket takes place as a result of cracks formation in the lower tension region and their constant diffusion onto the cover blanket surface. The number of repeated loads necessary for the cracks diffusion onto layer thickness exceeds the number of cycles before the appearance of the first fatigue crack in 20 times. Therefore, the asphalt concrete durability in a blanket exceeds the number of cycles "load-unload" without intervals in which asphalt concrete sample sustains up to fracture in the laboratory in 100 [12]

Operation ability factors of asphalt concrete reliability can be divided into two groups: external

To the external factors we can refer the environment influence of three types: mechanical, physical-climatic and chemical; to the internal: the indexes of quality, determining the asphalt

The typical fatigue peculiarity is the following: the load factor which is less than the destruc-

Bearing capacity and operation durability of asphalt concrete blanket are more completely

Dynamic state of road blanket depends on traffic flow concentration and composition and also

Traffic loads induce both deflections and oscillations in road blanket are conditioned by

While researching bitumen water resistance and adhesion to mineral powders in a laboratory it was proved that bitumen stresses exfoliation from the mineral material surface were comparatively small [14, 15]. In real operation conditions, the additional stresses appearing at traffic movement influence on the wet blanket exceed the thermodynamic ones. Practically, water presses into a blanket in front of the moving wheel and presses out from a blanket after a wheel. The results of such a pumping action are various and difficult for consideration.

At short-term contact of moving wheels with surface, the water pressure in pores of up to 0.05 cm radius is not enough for asphalt concrete fracture but for popcorn mixes it can reach

If the prolong temperatures are >50С the deformations of different types appear on an asphalt concrete blanket. The reason is the following: after heat accumulation in asphalt concrete layers, the degradation of bitumen viscosity takes place. According to the second law of thermodynamics (entropy), the grade of the temperature, concentration, barometric pressure always direct from the big value to small one. That is why bitumen starts to move upwards because its concentration is higher inside the asphalt concrete blanket than on the surface. Hereby there is its transition from structured state into the phase of free bitumen. The distance

concrete ability to resist the mentioned types of external one.

on the intervals between separate cars.

destruction quantity.

tive one leads to the progressive durability and degradation of road surface.

characterized by modulus of elasticity and tensile in bending strength.

momentary elasticity and elastic deflection of road constructions.

or 200 [13] times.

and internal.

98 Modified Asphalt

It was proved that the mechanism of accelerated fatigue fracture of water saturated asphalt concrete during surface under cyclic dynamic loads is conditioned in certain grade by the appearance of pulse hydrodynamic pressures in water saturated pores of between grains space. Experimental researches of fatigue properties of asphalt concrete while working in the water saturated state show that the service life before the fracture in water saturated state is shorter in 1.5–2.5 times in comparison with the asphalt concrete working in dry state [11, 16]. That is why the formation of pulse hydrodynamic pressures in pores of water saturated asphalt concrete under the moving cars dynamic loads is one of the main mechanisms of asphalt concrete fatigue in watering conditions [14].
