In Russia, the largest distribution was obtained by the search for the compositions of the mineral part of asphalt concrete mixtures on the limiting curves of grain compositions. A mixture of rubble, sand and mineral powder is chosen in such a way that the cereal curve is located in a zone limited by limit curves, and was smooth. The fractional composition of the mineral mixture is calculated depending on the content of selected components and their grain compositions by the following dependency:
j - number component;
n - the number of components in the mixture;
When selecting the grain composition of the asphalt concrete mixture, especially with the use of sand from crushing sections, it is necessary to take into account the grain-contained grain in the mineral material.
These dust particles can either be removed from the mixture, or dose to the mixing unit with mineral powder. The procedure for using dust capture is negotiated in the technological regulation on the preparation of asphalt concrete mixtures, taking into account the quality of the material and features of the asphalt mixing installation.
Next, in accordance with the combination of 12801-98, the average and true density of the asphalt concrete and the mineral part is determined and the residual porosity and porosity of the mineral part are calculated by their values. If the residual porosity does not correspond to the normalized value, then the new content of bitumen b (% by weight) is calculated by the following dependency:
With the calculated amount of bitumen, the mixture is prepared, formulate samples from it and again determine the residual porosity of the asphalt concrete. If it will correspond to the required, the calculated amount of bitumen is based on the basis. Otherwise, the procedure for selecting a bitumen content based on approximation to the normalized pore volume in the compacted asphalt concrete is repeated.
From the asphalt concrete mixture with a predetermined content of bitumen, the standard method of samples is molded by a standard sealing method and determine the full range of indicators of physicomechanical properties provided for in GOST 9128-97. If the asphalt concrete for any indicators does not respond to the requirements of the standard, the composition of the mixture is changed.
With an insufficient value of the inner friction coefficient, the content of large fractions of rubble or crushed grains in the sandy part of the mixture should be increased.
With low clutch indicators for shift and compressive strength at 50 ° C, it should be increased (under permissible limits) the content of the mineral powder or apply a more viscous bitumen. At high strength values \u200b\u200bat 0 ° C, it is recommended to reduce the content of the mineral powder, reduce the viscosity of the bitumen, apply polymer-bitumen binder or use plasticizing additives.
With insufficient water resistance of the asphalt concrete, it is advisable to increase the content of mineral powder or bitumen, but within the limits that ensure the required values \u200b\u200bof residual porosity and porosity of the mineral part. To increase the water resistance, essentially used surfactants (surfactants), activators and activated mineral powders. The selection of the composition of the asphalt concrete mixture is considered complete if all indicators of physicomechanical properties obtained by testing asphalt-concrete samples will meet the requirements of the standard. However, in the framework of the standard requirements for the asphalt concrete, the composition of the mixture is recommended to be optimized in the direction of increasing the operational properties and the durability of the arranged structural layer of road clothing.
The optimization of the composition of the mixture intended for the device of the upper layers of road surfaces until recently was associated with an increase in the density of asphalt concrete. In this regard, in road construction, three methods were formed, used in the selection of grain compositions of dense mixtures. Initially, they were called as:
- - Experimental (German) method of selection of dense mixtures, consisting in the gradual filling of one material to others;
- - method of curves based on the selection of grain composition approaching the predetermined mathematically "ideal" curves of dense mixtures;
- - American method of standard mixtures based on appraded mixtures of concrete materials.
These methods were offered about 100 years ago and were further developed.
The essence of the experimental method of selection of dense mixtures is to gradually fill the pores of one material with larger grains of other smaller mineral material. Practically selection of the mixture is carried out in the following order.
To 100, the weight parts of the first material are added sequentially 10, 20, 30, etc., the weight parts of the second, determining after mixing and sealing the average density and choosing a mixture with a minimum amount of voids in the compacted state.
If it is necessary to make a mixture of three components, then to a dense mixture of two materials add gradually increasing portions of the third material and also choose the most dense mixture. Although this selection of the dense mineral island time-consuming and does not take into account the effects of the content of the liquid phase and the properties of the bitumen on the compaction of the mixture, nevertheless it is still used in experimental research.
In addition, the experimental method of selection of dense mixtures was based on the calculated methods for the preparation of dense concrete mixtures of bulk materials of various lampsiness and was further developed in the methods of planning the experiment. The principle of consistent filling of voids was used in the method of designing the optimal compositions of road asphalt concrete concrete, in which crushed stone, gravel and sand with any granulometry are used.
According to the authors of the work, the proposed estimated experimental technique allows you to optimally control the structure, composition, properties and cost of asphalt concrete. The role of variable structural control parameters uses:
- - coefficients of sliding grains of rubble, gravel and sand;
- - bulk concentration of mineral powder in asphalt binder;
- - the optimal criterion of the composition, expressed by the minimum total value of components per unit of production.
On the principle of consistent filling of voids in crushed, sand and mineral powder, an estimated composition of the mixture for asphalt concrete density based on liquid bitumens was calculated.
The content of components in the mixture was calculated based on the results of the preset value of the true and bulk density of mineral materials. The final composition was specified experimentally when varying the content of all components of the mixture by the method of mathematical planning experiment on the simplex. The composition of the mixture providing minimal porosity of the mineral island of asphalt concrete was considered optimal.
The second method of selection of the grain composition of asphalt concrete is based on the selection of dense mineral mixtures, the grain composition of which is approaching the perfect curves of Fuller, Count, Herman, Bolomey, Talbot Richard, Kitt-Pepfa and other authors. These curves in most cases are subsequent dependencies of the desired grain content in the mixture of their size. For example, the curve of the particle size composition of the dense mixture on the fuller is given by the following equation:
D is the greatest grain size in the mixture, mm.
To normalize the grain composition of the asphalt concrete mixture in the modern American method of designing "SuperPave", granulometric curves of the maximum density, corresponding to the power dependence with the indicator of 0.45, are also taken.
Moreover, besides the control points that limit the range of grain content, the inner zone of the restriction is also given, which is located along the granulometric curve of the maximum density in the gap between the grains of 2.36 and 0.3 mm. It is believed that mixtures with a granulometric composition passing by the restrictive zone may have problems with sealing and shift stability, since they are more sensitive to the content of bitumen and become plastic in case of accidental overdose of organic binder.
It should be noted that GOST 9128-76 also prescribed a restrictive zone for curves of dense mixtures, located between the limit curves of continuous and intermittent granulometry. In fig. 1 This zone is shaded.
Fig. one. - The grain compositions of the mineral part of the fine-grained:
However, in 1986, when reproducing the standard, this restriction was canceled as insignificant. Moreover, in the works of the Leningrad branch of Somponia (A.O. Sal), it was shown that the so-called "semi-broker" compounds of mixtures in some cases preferably continuous due to lower porosity of the mineral part of the asphalt concrete, and intermittent - due to greater stability to bundle.
The domestic method for constructing curves of the particle size distribution of dense mixtures was the famous studies of V.V. The hunter, in which it was shown that the most dense mixture can be obtained provided if the diameter of the particles constituting the material will decrease in the proportion of 1:16, and the weights of their quantities are as 1: 0.43. However, given the tendency to segregation of mixtures, composed with this ratio of large and small fractions, was proposed to add intermediate fractions. In this case, the weight of the fraction with a diameter, 16 times smaller, will not change at all, if the emptiness is not simply filled with these fractions, but, for example, fractions with a grain diameter of 4 times smaller.
If when filling with fractions 16 times with a smaller diameter, their weight content was 0.43, then when filling with fractions with a diameter of grains, 4 times smaller, their content should be equal to \u003d 0.67. If you enter another intermediate fraction with a diameter that decreased by 2 times, the ratio of fractions should be k \u003d 0.81. Thus, the weight number of fractions that will decrease on the same value all the time, it can be expressed mathematically as a series of geometric progression:
Y1 - the number of the first fraction;
to - the escape coefficient;
n is the number of fractions in the mixture.
From the progression of the progression, the quantitative value of the first fraction is derived:
Thus, the escape ratio is made to call the weight ratio of fractions, the dimensions of the particles of which are treated as 1: 2, i.e., as the ratio of the nearest sizes of cells in the standard set of SIT.
Although theoretically, the most dense mixtures are calculated by the outfit ratio of 0.81, mixtures with intermittent grain composition were more dense.
This is explained by the fact that the theoretical calculations of the compilation of dense mixtures on the outfit ratio do not take into account the sliding of large grains of the material with smaller grains. In this regard, P.V. Sakharov noted that positive results from the point of view of increasing the density of the mixture are obtained only with a step (intermittent) selection of fractions.
If the ratio of the size of the mixed fractions is less than 1: 2 or 1: 3, then small particles do not fill the gap between large grains, and spread them.
The curves of the particle size composition of the mineral part of the asphalt concrete with various rebel coefficients are shown in Fig. 2.
Fig. 2. - Granulometric composition of the mineral part of the asphalt concrete mixtures with various Raceba coefficients:
Later, the ratio of the diameters of the particles of adjacent fractions, excluding the sliding of large grains in many fractional mineral mixtures, was specified. According to P.I. Bozhenova to eliminate the sliding of large grains with small, the ratio of the diameter of the shallow fraction to the diameter of the large fraction should be no more than 0.225 (i.e., as 1: 4.44). Given the composition of mineral mixtures proven in practice, N.N. Ivanov proposed to be used to seize mixtures a granulometric composition curve with a rank factor ranging from 0.65 to 0.90.
Granulometric compositions of dense asphalt concrete mixtures, focused on convenientness, were normalized in the USSR from 1932 to 1967. In accordance with these norms, the asphalt concrete mixtures contained a limited amount of rubble (26-45%) and an increased amount of mineral powder (8-23%). The experience of using such mixtures has shown that in coatings, especially on roads with severe and intensive movement, waves, shifts and other plastic deformations are formed. At the same time, the roughness of the surface of the coating was also insufficient to provide high adhesion with the wheels of cars, based on traffic safety conditions.
The fundamental changes in the standard for asphalt mixtures were made in 1967. GOST 9128-67 included new compounds of mixtures for framework asphalt concrete concrete (up to 65%), which began to provide in projects with high traffic intensity. The asphalt concrete mixtures also reduced the amount of mineral powder and bitumen, which justified the need to move from plastic to tougher mixtures.
The compositions of the mineral part Many crushed wall mixtures were calculated using a cubic parabolic equation tied to four control dimensions of grains: 20; 5; 1.25 and 0.071 mm.
In the study and implementation of the frame asphalt concrete, great importance was attached to the increase in coating roughness. The methods of the device of asphalt concrete coatings with a rough surface were reflected in the recommendations developed in the early 60s of the last century and received the initial introduction at the facilities of the Glavdorstroy Ministry of Transport of the USSR. According to developers, the creation of roughness should be preceded by the formation of a spatial frame in the asphalt concrete. Almost this was achieved by a decrease in the amount of mineral powder in a mixture, an increase in the content of large crushed grains, a complete seal of the mixture, in which grains of rubble and large sand fractions come into contact with each other. Obtaining an asphalt concrete with a frame structure and a rough surface was provided with a content of 50-65% by weight of grains larger than 5 (3) mm. In fine-grained mixtures of type A and 33-55% grains are larger than 1.25 mm. In the sandy mixtures of type r with a limited content of mineral powder (4-8% in fine-grained mixtures and 8-14% in sandy).
Recommendations for ensuring the effectability of asphalt concrete coatings as a result of the use of frame asphalt concrete, by increasing the internal friction of the mineral island and are also present in foreign publications.
For example, road firms from the UK during the construction of asphalt concrete coatings in tropical and subtropical countries specially apply grain compositions, selected by the equation of the cubic parabola.
The stability of coating from such mixtures is mainly due to the mechanical sugar of particles of angular shape, which must be either durable rubble or crushed gravel. Apply unfinished gravel in such mixtures is not allowed.
The resistance of the coating shift deformations can be increased by increasing rubble size. In the USATM D 3515-96 standard, asphalt concrete mixes were provided, differentiated by nine grades, depending on the maximum grain size of 1.18 to 50 mm.
The higher the brand, the larger the crushed stone and the lower the content of the mineral powder in the composition of the mixture. Curves grain compositions built on cubic parabole provide a hard frame of large grains during sealing coating, which has the main resistance to transport loads.
In most cases, the mineral part of the asphalt concrete mixture is selected from the coarse, mediterranean and fine-grained components. If the true density of the components of mineral materials differs significantly among themselves, the content of them in the mixture is recommended to calculate in volume.
Tested in practice, the grain compositions of the mineral part of the asphalt concrete mixtures are standardized in all technically developed countries, taking into account the field of their application. These compositions are usually consistent with each other.
In general, it is believed that the most developed element of the design of the composition of the asphalt concrete is the selection of the granulometric composition of the mineral part or by the optimal density curve, or on the principle of consistent pore fill. It is more difficult to deal with the choice of bitumen binders of necessary quality and with the rationale for its optimal content in the mixture. Until now, there is no single opinion on the reliability of the calculated methods for the purpose of the content of bitumen in the asphalt concrete mixture.
The current experimental methods of selection of the binding content involve different methods of manufacturing and testing asphalt-concrete samples in the laboratory and, most importantly, it is enough to reliably predict the durability and operational condition of the road surfaces depending on the operating conditions.
P.V. Sakharov offered to design the composition of the asphalt concrete at a pre-selected composition of the asphalt binder. The quantitative ratio of bitumen and mineral powder in the asphalt binder was selected experimentally depending on the plastic deformation indicator (by water removal) and on the tensile strength of the eight samples. The thermal stability of the asphalt binder with comparison of strength indicators at temperatures 30, 15 and 0 ° C was also taken into account. Based on the experimental data, it was recommended to adhere to the values \u200b\u200bof the ratio of bitumen to the mineral powder by mass (b / mp) in the range from 0.5 to 0.2.
As a result, the composition of the asphalt concrete was characterized by an increased content of mineral powder. In further research I.A. Fishkeva It was shown that the rational values \u200b\u200bof b / mp can be equal to 0.8 and even higher. Based on the strength of the strength of the optimal structures (the rule of the crust), the method of designing the composition of the asphalt concrete on the specified operating conditions of the road surface was recommended. It was stated that the optimal structure of the asphalt concrete is achieved when the bitumen is translated into a film state.
At the same time, it was shown that the optimal content of the bitumen in the mixture depends not only on the quantitative and qualitative ratio of components, but also from technological factors and sealing modes.
Therefore, the scientific substantiation of the required operational indicators of asphalt concrete and rational ways to achieve them continue to remain the main task associated with increasing the durability of road surfaces.
There are several calculated ways to prescribe bitumen content in the asphalt concrete mixture both by the thickness of the bitumen film on the surface of mineral grains and by the amount of voids in the compacted mineral mixture.
The first attempts of their use when designing asphalt concrete mixtures often ended in failure, which forced to improve the calculated methods for determining the content of bitumen in the mixture. N.N. Ivanov proposed to take into account the best sealability of the hot asphalt mixture and some stock on the temperature expansion of the bitumen if the calculation of the bitumen content is carried out on the porosity of the compacted mineral mixture:
B - the number of bitumen,%;
P - porosity of a compacted mineral mixture,%;
c6 - True bitumen density, g / cm. cube;
c is the average density of a compacted dry mixture, g / cm. cube;
0.85 - the coefficient of reducing the number of bitumen due to the best sealing of the mixture with bitumen and the bitumen expansion coefficient, which is taken equal to 0.0017.
It should be noted that calculations of the volumetric content of the component in the compacted asphalt concrete, including the volume of air pores or residual porosity, are performed in any method of design in the form of normalization of the phase volume. As an example in Fig. 3 shows the volume composition of the asphalt concrete type A in the form of a circular diagram.
Fig. 3. - Normalization of the phase volume in the asphalt concrete:
In accordance with this diagram, the content of bitumen (% by volume) is equal to the difference between the porosity of the mineral island and the residual porosity of the compacted asphalt concrete. So, M. Düyrie recommended a methodology for calculating the content of bitumen in a hot asphalt concrete mixture in the saturation module. The saturation module of the asphalt concrete binding substance was established according to experimental and production data and characterizes the percentage of binder in a mineral mixture having a specific surface of 1 mq / kg.
This technique is adopted to determine the minimum content of bitumen binder depending on the grain composition of the mineral part in the design method of the asphalt concrete mixture of LCPC. Developed by the central laboratory of bridges and roads of France. The weight content of the bitumen on this method is determined by the formula:
k is a module of saturation of asphalt concrete binder.
- S - Private residue on sieve with holes of 0.315 mm.,%;
- s is a private residue on sieve with holes of 0.08 mm.,%;
The method of calculating the content of bitumen in the thickness of the bitumen film significantly improved I.V. Queen. Based on the experimental data, they produced differentiation of the specific surface of the grains of standard fractions, depending on the nature of the rock. The influence of the nature of the stone material, the size of grains and viscosity of bitumen on the optimal thickness of the bituminous film in the asphalt mixture was shown.
The next step is the differentiated assessment of the bituminosity of mineral particles with smaller than 0.071 mm. As a result of the statistical prediction of the grain compositions of the mineral powder and bitmaking fractions of fractions from 1 to 71 μm in MADI (GTU), a technique was developed that allows us to obtain calculated data that satisfactorily coincide with the experimental content of bitumen in the asphalt concrete mixture.
Another approach to the purpose of the content of bitumen in the asphalt concrete is based on the dependence between the porosity of the mineral island and the grain composition of the mineral part. Based on the study of experimental mixtures from particles of various majority, Japanese specialists proposed a mathematical model of the porosity of the mineral island (VMA). The values \u200b\u200bof the coefficients of the established correlation dependence were determined for a crushed stone-mastic asphalt concrete, which was compacted in the rotational seal (hyporator) at 300 mold revolutions. The algorithm for calculating the content of bitumen based on the correlation of the pore characteristics of the asphalt concrete with the grain composition of the mixture was proposed in operation. According to the results of the processing of the data array obtained by testing dense asphalt concrete, the following correlations are established to calculate the optimal content of the bitumen:
K - Granureometry parameter.
DKR is the minimum grain size of a large fraction, which contains 69.1% by weight of the mixture, mm.;
D0 - the size of the grains of the middle fraction, the smaller of which contains 38.1% by weight of the mixture, mm.;
DMELK is the maximum grain size of a shallow fraction, the smoother of which contains 19.1% by weight of the mixture, mm.
However, in any case, the calculated bitumen dosages should be adjusted in the preparation of control injuries depending on the results of the test samples of the asphalt concrete.
When selecting the compositions of asphalt concrete mixtures, the following statement of prof is relevant. N.N. Ivanova: "bitumen should be taken no more than it is due to the production of a sufficiently strong and stable mixture, but the bitumen must be taken possible more, and in no case maybe less." Experimental methods of selection of asphalt concrete mixtures usually suggest the preparation of standard samples given by the specified methods of sealing and testing them in laboratory conditions. For each method, appropriate criteria are developed that establish a link between the results of laboratory tests of compacted samples and the operational characteristics of the asphalt concrete under operating conditions.
In most cases, ZGI criteria are defined and standardized by national standards on asphalt concrete.
The following schemes of mechanical tests of the asphalt concrete samples are distributed, presented in Fig. four.
Fig. four. - Test schemes of cylindrical samples when designing the composition of the asphalt concrete:
a - in Dultsu;
b - by Marshall;
in - by kvimim;
mr. Hubbard Field.
An analysis of the various experimental methods for the design of the composition of the asphalt concrete indicates the similarity in approaches when prescription and the difference in the test methods and in the criteria of the estimated properties.
The similarity methods for the design of the asphalt concrete mixture is based on the selection of such a volumetric ratio of components in which the predetermined values \u200b\u200bof residual porosity are ensured and the normalized indicators of the mechanical properties of the asphalt concrete.
In Russia, in the design of the asphalt concrete, there are tests of standard cylindrical samples on a uniaxial compression (according to Dageza scheme), which are molded in the laboratory according to GOST 12801-98, depending on the content of rubble in a mixture or a static load of 40 MPa, or a vibration method with subsequent additional load seal 20 MPa. In overseas practice, the method of designing asphalt concrete mixtures in Marshall was the greatest distribution.
In the US, until recently, the methods of designing asphalt concrete mixtures in Marshall, Hubbardo-Filth and Quimea are applied. But recently, the SuperPave design system is introduced in a number of states.
When developing new methods for the design of asphalt concrete mixtures abroad, much attention was paid to improving the methods of sealing samples. Currently, when designing mixtures in Marshall, three levels of sample seal are provided: 35, 50 and 75 of the strikes on each side, respectively, for the conditions of the lung, medium and intensive movement of vehicles. The United States engineering troops, conducting extensive studies, improved the tests according to the Marshall method and distributed it to the design of mixtures for airfield coatings.
The design of the asphalt concrete mixture according to the Marshall method assumes that:
- - preliminarily established the initial mineral materials and bitumens of the requirements of technical specifications;
- - selected granulometric composition of a mixture of mineral materials satisfying project requirements;
- - the values \u200b\u200bof the true density of viscous bitumen and mineral materials are determined by the corresponding test methods;
- - A sufficient amount of stone material was dried and divided into fractions to prepare laboratory mixtures with different binder content.
For tests according to the Marshall method, standard cylindrical samples are made of 6.35 cm high. And a diameter of 10.2 cm. When sealing the incident cargo. The mixtures are prepared with different content of bitumen, usually different from another 0.5%. It is recommended to prepare at least two mixtures with a bitumen content above the "optimal" value and two mixtures with a bitumen content below the "optimal" value.
In order to more accurately assign the content of the bitumen to conduct laboratory tests, it is recommended to initially set the approximate "optimal" bitumen content.
Under the "optimal" implies the content of bitumen in the mixture, which ensures maximum stability by the Marshall molded samples. Approximately for the selection, it is necessary to have 22 south of stone materials and about 4 liters. bitumen.
The test results of the asphalt concrete according to the Marshall method are shown in Fig. five.
Based on the test results of the samples of asphalt concrete according to the Marshall method, usually come to the following conclusions:
- - the value of stability increases with an increase in the content of the binder to a certain maximum, after which the resistance value is reduced;
- - the value of the conditional plasticity of the asphalt concrete increases with increasing the content of the binder;
- - the dependence of the density density on the content of the bitumen is similar to the stability curve, however, for it, the maximum is more often observed with a somewhat higher content of bitumen;
- - the residual porosity of the asphalt concrete is reduced by increasing the content of the bitumen, approaching asymptotically to the minimum value;
- - The percentage of pore pores is increased with increasing bitumen content.
Fig. five. - Results (A, B, B, D) Tests of asphalt concrete according to the Marshall method:
The optimal content of the bitumen is recommended to be defined as the average of the four values \u200b\u200bset by schedules for the relevant design requirements. The asphalt concrete mixture with the optimal content of bitumen should satisfy all the requirements for technical specifications. In the final selection of the composition of the asphalt mixture, technical and economic indicators may also be taken into account. It is usually recommended to choose a mixture with the highest marshall stability.
However, it should be borne in mind that mixtures with excessively high values \u200b\u200bof Marshall and low plasticity are undesirable, as coatings from such mixtures will be overly rigid and can crack when driving heavy vehicles, especially with fragile bases and high coating deflection. Often in Western Europe and in the United States, the method of designing an asphalt concrete mixture in Marshall is criticized. It is noted that the shock sealing of samples in Marshall does not model the sealing of the mixture in the coating, and the stability of Marshall does not allow to satisfactorily assess the strength of the asphalt concrete during the shift.
The method of CVIMA is also criticized, the disadvantages of which include pretty bulky and expensive test equipment.
In addition, some important volume of the metric indicators of asphalt concrete associated with its durability in this method are not properly disclosed. According to American engineers, the method of choosing the content of bitumen by CVIMU is subjective and can lead to the briefness of the asphalt concrete due to the purpose of the low content of the binder in the mixture.
The LCPC (France) method is based on the fact that the hot asphalt concrete mix must be designed and sealed during the construction process to maximum density.
Therefore, special studies of the calculation of the seal were carried out, which was determined as 16 passes of a roller rink with pneumatic tires, with a load on the axis of 3 vehicles at a pressure of a tire 6 bar. On a full-scale laboratory stand, a standard layer thickness equal to 5 maximum sizes of mineral grains was substantiated in the compaction of the hot asphalt concrete mixture. For the appropriate sealing of laboratory samples, the angle of rotation on the laboratory seal (the hyporator) equal to 1 ° was standardized, and the vertical pressure on the sealing mixture of 600 kPa. At the same time, the standard number of rotations of the hyporator should be a value equal to the thickness of the layer of a sealing mixture, expressed in millimeters.
In the American method of designing the "SuperPave" design system, it was customary to convene samples from the asphalt of a concrete mix also in the hyporator, but at an angle of rotation of 1.25 °. Work on the sealing of samples of asphalt concrete is normalized depending on the calculated value of the total transport load on the coating, for the device of which the mixture is designed. The sealing pattern of the samples from the asphalt concrete mixture in the device of the rotational seal is shown in Fig. 6.
Fig. 6. - Scheme of sealing samples from asphalt concrete mixture in the rotational seal device:
In the design method of the MTQ asphalt concrete mixture (Quebec, Canada's Ministry of Transport) is borrowed by the SUPERPAVE rotational seal instead of the LCPC hypoator. The calculated number of rotations during the seal is taken for mixtures with a maximum grain size of 10 mm. equal to 80, and for mixtures of 14 mm. - 100 revolutions of rotation. The calculated maintenance of air holes in the sample must be from 4 to 7%. The nominal pore volume is usually 5%. The effective volume of bitumen is set for mixtures of each type, as in the LCPC method.
It is noteworthy that when designing asphalt concrete mixes from the same materials according to the Marshall method, the LCPC method (France), the SuperPave design system (USA) method and the MTQ (Canada method) method were obtained about the same results.
Despite the fact that each of the four methods provided for various conditions of sample seals:
- - Marshall - 75 blows from two sides;
- - "SuperPave" - \u200b\u200b100 rotation revolutions in the hyporator at an angle of 1.25 °;
- - MTQ - 80 rotation revolutions in the hyporator at an angle of 1.25 °;
- - LCPC - 60 revolutions of rotation of an effective seal at an angle of 1 ° C were obtained quite comparable results on the optimal content of bitumen.
Therefore, the authors of the work came to the conclusion that it was not important to have a "right" method of sealing laboratory samples, but to have a system of influence of the sealing effort on the structure of the asphalt concrete in the sample and on the performance of it in the coating.
It should be noted that the rotational methods of compaction of asphalt concrete samples are also not devastable. A noticeable abrasion of the stone material was established when the hot asphalt mixture is sealing in the hyporator.
Therefore, in the case of the use of stone materials characterized by wear in the Los Angeles drum, more than 30%, the normalized number of rotation of the mixture seal when producing samples of a rubbed-mastic asphalt concrete are prescribed 75 instead of 100.
The most used road-building material in the 20th century - asphalt - is divided into many species, grades and types. The base for the separation is not only and not so much the list of source components included in the asphalt concrete mixture, as well as the ratio of their mass fractions in the composition, as well as some characteristics of the components - in particular, the size of the fractions of sand and rubble, the degree of purification of the mineral powder and all the same sand.
The composition of Asphalt
In the asphalt of any type and brand there are sand, crushed stone or gravel, mineral powder and bitumen. However, it is not used when preparing some types of road surfaces, it is not used - but if the asphalting of the territories is carried out taking into account high traffic and strong short-term coating loads, then crushed stone (or gravel) is necessary - as a carcass-forming protective element.
Mineral powder - Mandatory initial element for the preparation of asphalt of any brands and types. As a rule, the mass fraction of the powder - and it is obtained by crushing rocks in which the high content of carbon compounds (in other words - from limestone and other organic ordering sediments) is determined based on the tasks and requirements for the viscosity of the material. The large percentage of mineral powders allows you to use it in such works as asphalting roads and sites: viscous (that is, durable) the material will successfully extinguish the internal oscillations of bridge structures, not cracking.
In most types and stamps asphalt used sand - Exception, as we said, make up the types of road surface, where the mass fraction is great gravel. The quality of the sand is determined not only by its degree of cleaning, but also by the method of receipt: the sand produced in the open method needs, as a rule, in a thorough cleaning, but the sand is artificial, obtained by crushing rocks, is considered ready "to work".
Finally, bitumen - The cornerstone of the road coating industry. The product of oil refining, bitumen is contained in a mixture of any brand in a very small amount - its mass fraction in most varieties hardly reaches 4-5 percent. Although, widely used with such works as asphalting of territories with complex reliefs and repair roads, cast asphalt boasts a bitumen content of 10 or more percent. The bitumen gives such a canvas a fair elasticity after hardening and fluidity that allows you to easily distribute the finished mixture on the site.
Stamps and types of asphalt
Depending on the percentage of the listed components, mix three asphalt brands. Specifications, scope and composition of the mixture of various brands are described in GOST 9128-2009, in which, among other things, it is also taken into account and the ability to add additional additives that increase the frost resistance, hydrophobicity, flexibility or wear resistance of the coating.
Depending on the percentage of filler contained in the road-building mixture, it is divided into the following types:
- A - 50-60% rubble;
- B - 40-50% rubble or gravel;
- In - 30-40% of rubble or gravel;
- G - up to 30% of sand from scratching;
- D - up to 70% of sand or mixture with crushing docks.
Asphalt brand 1.
Under this brand, a wide range of various types of coatings is made - from dense to high-art, with a significant content of rubble. The area of \u200b\u200buse - Road construction and landscaping: only porous materials are not at all suitable for the role of the coating actually, the upper layer of the road canvase. It is much better to apply them for the base device, aligning the base for laying more dense types of material.
Asphalt brand 2.
The density range is approximately the same, however, the content and percentage ratio of sand and gravel can vary in very wide limits. This very "average" asphalt, with a very extensive scope of application: And the construction of roads, and the repair of them, and the arrangement of the territories for parking and the square do not fail without it.
Asphalt brand 3.
The coatings of the brand 3 are distinguished by the fact that crushed stone or gravel is not used - they are replaced by mineral powders and especially high-quality sand, obtained by crushing solid rocks.
Sand and rubble ratio (gravel)
The ratio of the content of sand and gravel is one of the most important indicators that determines the scope of application of one or another type of coating. Depending on the prevalence of one or another material it is denoted by letters from A to D: A - more than half consists of fine-sided rubble or gravel, and d - about 70 percent consists of sand (though, sand is used for the most part of crushed rocks).
Bitumen ratio and mineral components
No less important - after all, it is precisely it determines the strength characteristics of the roadway. The high content of mineral powders significantly increases its fragility. therefore sand asphalt can only be used limited: Improvement of the territories of parks or sidewalks. But coverings with a large content of bitumen - the desired guest on any work: especially if it is road construction in harsh climatic conditions, at minus temperatures, if the speed of work is such that already a day after a new cannon will go road equipment, and after the finished road - True heavy trucks.
It is largely dependent on the properties of the ingredients of the mixture and their ratio.
There are several types of asphalt concrete, the composition of which is noticeably different. In some cases, the composition and quality of the initial ingredients turns out to be related to the production method.
- So, for 1-3 climatic belts, dense and highly qualified ab are made of rubble, whose class of frost resistance is F50. Porous and highly porous - from stone class F 15 and F25.
- For zones 4 and 5, only high-detached hot asphalt is performed on the basis of rubble class F 50
We will talk about the role of sand as picked up asphalt concrete.
Sand
Available in any kind of AB, but in some - sand asphalt concrete, it acts as the only mineral part. Apply both natural - from quarries and the resulting by the screening during crushing. Requirements for material dictation GOST 8736.
- So, for dense and highly discovered sand with a class of strength of 800 and 1000. For porous - decreases to 400.
- The number of clay particles - in diameter less than 0.16 mm, is also adjustable: for dense - 0.5%. For porous - 1%.
- Increases the ability of AB to swelling and reduces frost resistance, so it is particularly followed by this factor.
Mineral powder
This part forms a binder with bitumen. Also, the powder fills the pores between large stone particles, which reduces the internal friction. Grain sizes are extremely small - 0, 074 mm. Get them from the dust collectors system.
In fact, the mineral powder is made from waste of cement enterprises and metallurgical - it is dust-carrying cement, ashlake mixtures, waste recycling of metallurgical slags. Grain composition, the amount of water-soluble compounds, water resistance and other adjusts GOST 16557.
Additional components
To improve the composition or giving some specific properties, various additives are introduced into the initial mixture. Share them for 2 main groups:
- components developed and manufactured specifically to improve properties - plasticizers, stabilizers, substances that prevent aging and so on;
- waste or secondary raw materials - sulfur, granulated rubber and so on. The cost of such additives is of course much less.
The selection and design of the composition of the road and airfield asphalt concrete are discussed below.
About selection of samples to assess the composition and quality of asphalt concrete will tell the video below:
Design
The composition of the coating device from the asphalt concrete is selected based on the destination: the street in a small town, the highway and the bicycle path require different asphalt. To get the best coating, but at the same time not to overcome the materials, the following selection principles use.
Basic principles
- The grain composition of the mineral ingredient, that is, stone, sand and powder, is basic to ensure the density and roughness of the coating. Most often use the principle of continuous granulometry, and only in the absence of large sand - the method of intermittent granulometry. Grain composition - particle diameters and their correct ratio, must fully correspond to that.
The mixture is selected in such a way that the curve is placed on the site between the limit values \u200b\u200band did not include fractures: the latter means that an excess one is observed or a lack of some fraction.
- Various types of asphalt can form a frame and frameless structure of the mineral component. In the first case, rubble enough so that the stones come into contact with each other and the finished product formed a clearly pronounced structure of the asphalt concrete. In the second case, stones and grains of large sand do not come into contact. A somewhat conventional boundary between the two structures is the content of rubble in the range of 40-45%. When selecting this nuance must be considered.
- The maximum strength guarantees crushed stone cuboid or tetrahedral form. Such a stone is the most wearless.
- Surface roughness reports 50-60% of rubble from hard-pointed rocks or sand from them. Such a stone retains the roughness of natural chip, and this is important to ensure the adequacy of the asphalt.
- In general, asphalt based on crushed sand is more shifted than based on the career due to the smooth surface of the latter. For the same reasons, durability and durability of material based on gravel, especially marine less.
- Excess grinding of the mining machine leads to an increase in porosity, and, it means that bitumen consumption. And such property has most industrial waste. To reduce the parameter, the mineral powder is activated - treated with surfactants and bitumen. Such a modification not only reduces the content of bitumen, but also increases the water and frost resistance.
- When selecting bitumen, it is necessary to focus not only on its absolute viscosity - the higher it is higher, the higher the density of the asphalt, but also on the weather conditions. Thus, in arid areas, the composition is selected, providing the minimum possible porosity. In cold mixtures, on the contrary, the bitumen is reduced by 10-15% to reduce the level of hellight.
Selection of composition
The selection procedure is generally the same:
- evaluation of the properties of mineral ingredients and bitumen. This refers not only absolute indicators, but their compliance of the ultimate goal;
- calculate such a ratio of stone, sand and powder so that this part of the asphalt acquires the highest possible density;
- lastly, the amount of bitumen is calculated: sufficient to provide the desired technical properties of the finished product on the basis of the selected materials.
First, theoretical calculations are carried out, and then laboratory tests. First of all, the residual porosity is checked, and then the correspondence of all other characteristics are supposed. Calculations and tests are carried out until a mixture is obtained that fully satisfying the task.
As with all sorts of complex building material, AB has no one-valued qualities - density, specific gravity, strength, and so on. Its parameters determine the composition and method of preparation.
On how the design of asphalt concrete composition in the United States, the next cognitive video will tell:
The calculation is the selection of rational relationship between the components of the asphalt concrete mixture with materials.
Wide distribution received a method for calculating the curves of dense mixtures. The greatest strength of the asphalt concrete is achieved at the maximum density of the mineral island, the optimal amount of bitumen and mineral powder.
There is direct dependence between the grain composition of mineral material and density. The optimal compositions containing grains of various sized, the diameters of which are reduced by two times.
where d. 1 - the largest diameter of the grain, mounted depending on the type of mixture;
d. 2 - the smallest diameter of the grain corresponding to the dustless fraction, and mineral powder (0.004 ... 0.005 mm).
Grain sizes, according to the previous level
(6.6.2)
The number of sizes are determined by the formula
(6.6.3)
Number of fractions p per unit less than the number of sizes t.
(6.6.4)
The ratio of neighboring fractions by mass
(6.6.5)
where TO - Razba coefficient.
The value indicating how many times the amount of the subsequent fraction is less than the previous one, is called the escape coefficient. The most dense mixture is obtained with a range of 0.8, but it is difficult to choose such a mixture, therefore, at the proposal of N.N. Ivanova, Ranger Fatiff TO Adopted from 0.7 to 0.9.
Size: px.
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Transcript.
1 system of regulatory documents in construction Standard enterprise Procedure for the selection and coordination of recipes of asphalt concrete mixtures STP Directorate of the regional road Fund Kemerovo Preface
2 1. Developed by an autonomous non-profit organization "KuzbassdorsDorsdism" (Cand. Tech. Sciences, Assoc. O.P. Athenogenov, Inzh. V.B. Sadkov). 2. Made by the Autonomous Non-Profit Organization "KuzbassdorRertification". 3. Approved and commissioned by the State Institution "Kemerovo Directorate of the Regional Road Fund". 4. Entered for the first time. GU "Kemerovo Dir. region. Fund ", 2000 Standard of the enterprise The order of the selection and approval of the recipes of asphalt mixtures was introduced for the first time approved and commissioned by order of March 13, 2001, 31
3 1. Scope of the introduction This standard establishes the basic requirements for the procedure for selecting asphalt-concrete mixtures recipes, the order of their coordination when performing road works under contracts with the State Institution "Kemerovo Directorate of the regional Road Fund" (in the future, the Customer, KEM "Kemerovo Dodph"). 2. Regulatory references This standard uses references to the following regulatory documents: SNiP system of regulatory documents in construction. Basic provisions; Snip car roads; SNIP *. Organization of construction production; GOST Testing and quality control of products. Main terms and definitions; GOST mixture asphalt concrete road, airfield and asphalt concrete; GOST Materials based on organic binders for road and airfield construction. Test methods; STP Preparation of road bitumens modified by attactic polypropylene. Standard regulation; TU Bitumes traffic modified by astactic polypropylene. 3. Definitions 3.1. The present standard uses the terms and their definitions corresponding to GOST 9128, GOST 16504, SNiP, SNIP asphalt concrete mixture rationally selected mixture of mineral materials (rubble [gravel] and sand with mineral powder or without it) with bitumen taken in certain ratios and mixed in Heated condition. Asphalt concubitated asphalt concrete mixture. A recipe for an asphalt concrete mix. A document that is part of the technological regulation containing information characterizing the scope of the mixture, its composition and physicomechanical properties, consumption of materials; Approved and agreed in the prescribed manner. 4. General provisions
4 4.1. The contractor does not have the right to carry out work using asphalt concrete mixes at the Kemerovo Dodph GU facilities without recipes for their production, consistent with the regulated present standard, the recipe is drawn up for the construction season, for each mixture used on this facility. It is allowed to issue one recipe for several similar objects in the case of adjusting the recipe based on the results of production control, when replacing materials, etc., the recipe is re-coordinated in the manner prescribed by the recipe section must comply with the requirements of project documentation, SNiP, GOST, other regulatory documents ( EAST, STP, etc.) The selection of the composition of the asphalt concrete mixture should be carried out by an organization with a competent laboratory and guaranteeing the reliability of the test results and the completeness of the controlled signs (characteristics) of the asphalt concrete mixture of the competent is the laboratory accredited to the appropriate types of tests in the registered and (or ) the system accreditation system recognized in the prescribed manner, or having a certificate of an official assessment of the measurement states, according to the asphalt concrete mixture, is composed on the basis of a specially performed selection, the purpose of which is to provide mixtures The selection properties (design) of the mixture consists of five stages: 1) the establishment of the requirements for the mixture; 2) the choice of materials and assess their suitability; 3) determination of the rational quantitative ratio of the components of the mixture; 4) quality control of the composition; 5) Economic assessment of the quality of the composition The task for the design of the asphalt concrete mixture issues the chief engineer of the contracting organization. The mixture can be selected by the road-building laboratory of a contractor or a laboratory attracted by the design of the mixture in the design of the mixture: the type of asphalt concrete mixture (hot, cold, coarse, fine-grained, sandy); View of asphalt concrete (highly discovered, dense, porous, highly porous); The type of mixture and the grade of asphalt concrete; Desired materials in the design of asphalt mixtures should strive to obtain the most economical composition. 5. Purpose of the basic parameters of the mixture 5.1. The main parameters and the type of mixture (asphalt concrete) are assigned by project documentation. If there were deviations from the requirements of the regulatory documents acting at the time of the selection of the mixture, it is necessary to coordinate the parameters with the customer. Asphalt concrete mixes must
5 Apply in accordance with P SNIP, ad. A GOST and meet the requirements of GOST Customer has the right to establish higher asphalt concrete mixtures (asphalt concrete) than it is planned to be reduced (with appropriate contractor cost compensation) for the device of the lower coating layer, leveling layers should be used mainly coarse-grained mixtures with a rough surface (to ensure Reliable clutch with the upper layer) and high-resistant-resistant in intensive movement should be used hot high-discovery mixtures of type A for the repair of small damage to the asphalt concrete coatings, mixtures close by properties to the mixtures of the repaired layer of the coating layer are used. 6. Selection of components of the mixture 6.1. Materials used for the preparation of asphalt mixtures must comply with the requirements of GOST, it is advisable to use crushed stone from erupted or metamorphic main and carbonate rocks with a better clutch with an oil bitumen. In shape, crushed stone should approach Cuba and not have flat bodybuilding grains. Gravel is an less desirable component, as it has a smooth surface, the inclusion of weak rocks. An increase in the amount of rubble increases the crack resistance and the shifting of the coatings is desirable to use sand consisting of particles of different sizes. Non-dimensional sand increases the porosity of the mineral part. Sand from seferences of crushing contributes to an increase in the internal friction of the mineral part through the contents of the grains of the acute-angular form in it. River sand is not recommended for asphalt concrete mixtures. Mineral powders obtained by artificial grinding of limestone and dolomites should be used. The presence in the mineral powder of very small clay particles increases the swelling of the asphalt concrete at moisturizing, increases the bitmapiness of the mixture. A large number of particles are larger than 0.071 mm increases the consumption of mineral powder and complicates the process of preparation and laying the mixture of the binding properties largely predetermine the quality of the asphalt concrete. Excessive bitumen viscosity leads to the formation of cracks at low temperatures, and low viscosity to plastic coating deformations in hot weather. In accordance with the requirements of SNiP in the conditions of the Kemerovo region, polymer-bitumen binders should be applied (modified bitumen). Polymer-bitumen binding brands of PBV, "Caudest-D", bitumen-commercial bcv brands are used, allowed on the territorial roads to apply Atthantic polypropylene of the APP G / B (binding, the binding should meet the requirements of the preparation of bitumens,
6 modified by astactic polypropylene is carried out under STP polymer additives increase the elasticity of bitumen, its thermal stability in a wide temperature range, strength and corrosion stability of the asphalt concrete. It should be borne in mind that with a lack or excess of bitumen, the mechanical strength of concrete decreases. With an increase in the amount of bitumen, the waterproofness of the asphalt concrete increases due to the more complete roasting of the stone materials with a bitumen film and filling the pores, and heat resistance decreases. With a decrease in the number of bitumen, the opposite phenomenon is observed: water testing increases, waterproofability decreases, and heat resistance rises, concrete becomes more rigid and fragile. 7. Calculation of the composition of the mixture 7.1. The design of the composition of the asphalt concrete mixture (asphalt concrete) is allowed to be performed according to any well-known method. It is recommended to use the method of juice, to which the GOST base is based on the assumption that concrete strength is due to its structure and is ensured by the creation of a dense mineral mixture with the optimal amount of bitumen in the conditions of the Kemerovo region, it is advisable to strive for the use of a smaller amount of sand and mineral powder having a greater moisture content, T .. Use the mixtures of types A and B calculation of the asphalt concrete includes two stages: the calculation of the particle size distribution (grain) composition of the mineral part of the mixture of a given set of materials according to the tables of the particle size distribution (Table 2 and 3 GOST); Experimental definition of physico-mechanical indicators of asphalt concrete, assessment of their compliance with the requirements of GOST, as well as the selection of the optimal amount of bitumen by testing test samples with the same composition of stone materials and a different bitumen content of the criterion for determining the optimal amount of bitumen is the best compliance of water saturation and mechanical compressive strength at temperatures 20 C and 50 with trial samples with appropriate requirements of GOST example calculation of the composition of fine-grained mixture 8.1. Task: Calculate the composition of fine-grained hot asphalt concrete type B, brand II. Components: Crushed stone Moszhukhinsky career, fractions 5-20 mm; Sand of the egg plant of building materials;
7 Mineral powder limestone. Calculation procedure. Based on the limits of the required granulometric compositions (Table 3 GOST) and according to the results of the sifting of the used mineral materials (Table 1), we determine the estimated percentage of each material (rubble, sand, mineral powder). Table 1 Name of material, manufacturer or quarry Private residues (quantity of grains,% by weight, less remaining on sieve with cell size, mm), 5 1,25 0,63 0.315 0.14 0.071 Less crushed stone Mozyukhinsky career, FR MM Sand KSM Mineral powder 5.3 33.7 30.2 23.6 3.7 3.5 1.0 18.5 17, 7.5 12.4 24.6 8.8 4.2 6.0 1, 2 2.0 8.6 16.6 71.6 The content of rubble x a 45 \u003d 100 \u003d 100 \u003d 48.49% B 92.8 whereas the average value of the total residues on the sieve with a diameter of 5 mm required by Table. 3 GOST; B The content of the fraction is larger than 5 mm in crushed. The content of mineral powder A1 6 Z \u003d 100 \u003d 100 \u003d 8.4% B 71.6 1 where A1 is the minimum allowable content of the fraction "less than 0.071 mm" in the composition of the asphalt concrete type B (Table 3 GOST); B1 The fraction content is smaller than 0.071 mm in mineral powder. Given the presence of grains in the sand of more than 5 mm in the sand and smaller than 0.071 mm, we reduce the value of the content in the graffer mixture and mineral powder obtained above, up to the following values: rubble 42.0%, mineral powder 7.0%. Then the sand content in the mixture is fill in table 2. y \u003d 100 (x + z); Y \u003d 100 (42 + 7) \u003d 51%
8 Moving data Count 10 with data Count 11 suggests that the composition of the projected mineral part of the asphalt concrete mixture corresponds to the required compositions of dense mixtures. Table 2 Calculated table for determining the full residues of the designed mineral mixture sizes of the sieve in mm Granulometric composition of the components of materials in% rubble sand Mineral powder Granureometric composition of materials in the designed mixture in% crushed stone Mineral powder Private residues of the projected mineral mixture in% full residues of the projected mineral mixture in% full passages Permissible limits of complete passages according to GOST, 3 2.2 2.2 2.2 97.7 14.2 14.2 16.4 83.2 1.0 12.6 0.5 13.1 29, 5 70.6 18.5 9.9 9.4 19.3 48.8 51.5 3.7 17.0 1.6 8.7 10.3 59.1 40.25 3.5 7.5 1 , 5 3.8 5.3 64.4 36.63 12.4 1.2 6.3 0.1 6.4 70.8 29,315 24.6 2.0 12.5 0.1 12.6 83, 4 16,14 8.8 8.6 4.6 0.6 5.2 88.6 11.071 4.2 16.6 2.1 1.2 3.3 91.9 8, less than 6.0 71.6 3.1 5.0 8, we determine the percentage of the bitumen in accordance with the recommendations of the GOST application, it is 5.0-6.5%. Based on this, we prepare three asphalt concrete mixtures with the same mineral composition and the calculated amount of bitumen (5.0-5.8-6.5%). From these compositions, test samples are made, which are tested on compression at a temperature of +20 and +50 s and water saturation. For the optimal amount of bitumen, its content is taken, in which the best asphalt concrete rates were achieved. We manufacture control samples of the projected composition with the optimal amount of bitumen and expose them to a complete test cycle. Test results We enter Table 3. Table 3 Asphalt properties indicators
9 Name Indicator Requirements GOST Actual Indicators Name Indicator Requirements GOST Actual Indicators Middle Density, 2.38 Water Resistant at r / cm 3 long-term water saturation Porosity Mineral Parts in volume,% residual porosity,% 19 16.3 Coupling bitumen with mineral part 2,5 5.0 3.4 Indicator Exchangeability Water saturation,% 1.5 4.0 2.8 Fragment resistance rate Compression tensile strength at a temperature, MPa Total specific effective activity of natural radionuclides, BC / kg 0.75 0.87 Withstand withstands from 2 , 2 2.6 50 C 1.0 1.1 0 C 12.0 10.0 Water resistance 0.85 0.93 Indicators of shifting and crack resistance are determined if they are normalized by the project documentation for the construction of an asphalt concrete coating. We calculate the composition of the asphalt concrete mixture for one mixer kneading. The source data is the mass of the kneading and the size of the cells of the sieve of the root of hot materials installed on the para. For an ABZ DS mass of the kneading is 600 kg, sieve with cells 5, 15, 35 mm are installed on the screen. The mass of the material that must be received from the bunker to the knead, is equal to (F1 F2) 600 d i \u003d, 100 b where i the number of the bunker, from which the material is set to the knee; F1 Full residue on the underlying sieve in% is made according to Table data. 2; F2 Full residue on the overlying sieve in% is made according to Table data. 2; 600 mass of kneading, kg; B percentage of bitumen in the mixture;
10 (100 48.8) 600 d 0 5 \u003d \u003d 289.8 kg; 100 1.06 (48.8 16.4) 600 d 5 15 \u003d 183.4 kg 100 1.06 (16.4 0) 600 d \u003d \u003d 92.8 kg, 06; Since mineral powder is supplied by a separate feed line, from the mass of the material shipped from the bunker D0-5, it is necessary to calculate the mass of the mineral powder "289, d 0 5 \u003d 289.6 39.6 \u003d 250 kg; 100 1.06 results of calculations We enter in Table 4. The composition of the asphalt concrete mixture binder or fraction of stone materials in accordance with the dosage on the ZAmes 600 kg of hot bunkers of paras 1 fraction mm 92.8 2 Frosculation 5-15 mm 183.4 3 fraction 0-5 mm 250.0 4 mineral Powder 39.6 5 bitumen 34.2 Table 4 Calculate the consumption of the asphalt concrete mixture per 1000 m2 coating and the flow rate of the components by 100 tons of the mixture, the results we enter in Table 5. V \u003d HSG \u003d 0.38 \u003d 95.2 T, where v asphalt concrete mixture, T; H layer thickness, m; s area of \u200b\u200blayer, equal to 1000 m2; G Average density of asphalt concrete, from table. 3, t / m. 3. It is necessary to take into account that in some cases the Customer agrees to pay the contractor with unreasonable losses, as a rule It is 3% of the volume of asphalt concrete. V "W 100 \u003d P (100 + C),
11 where V "The consumption of inert stone materials, m 3; W percentage of this material in the mixture; p. Solid-bulk mass of stone materials; C percentage of bitumen in the mixture." V 1 \u003d 28.5 m 1.39 () " V 2 \u003d 33.0 m 1,46 () Material consumption 3 3 ;; Table 5 per 100 TSMEs per 1000 m 2 Coatings Name of material bulk density, t / m 3 Contents in mixture in% t m 3 Crushed stone 1.5 Mozyukhinsky Career Sand of the Egg KSM 1, Mineral Powder 7 6.6 bitumen 6 5.7 Asphalt concrete mixture (T), with a layer thickness, 2 9. Registration of the recipes of the mixture 9.1. A separate recipe is made to each mixture, which must have an individual number consisting From the sequence number in this year and the last two digits of the year to which it is drawn up (for example, 14-00). The ordinal numbers must comply with the registration numbers according to the "magazine of determining the physico-mechanical properties of asphalt concrete mixtures in the selection of compositions and periodic quality control of the produced asphalt mixture and "(form d-7) Recipes are drawn up on typical blanks, in the form given in the application. All entries should be clear and neat, the text is not allowed, blots. The following design options are allowed: with the help of a personal computer; On a blank from hand, ink (paste) of black or blue. The second and third instance of the recipe can be photocopy. For examination and approval, 3 copies of the recipe approved by the Chief Engineer (Technical Director) of the Organization (indicating the date of approval, surnames, the initials of the approving, the name of the contractor's enterprise. Signature is assigned to seal.
12 It is forbidden to represent photocopy of recipes where the signature and printing the organization performing the examination are copied, the Customer has the right to not consider recipes decorated with violation P in the recipe indicate a structural element in which the mixture is used (top, bottom layer of coating, base), view, type and the brand of the mixture (asphalt concrete), the object, for example: "... for the device of the upper coating layer (hot, type A, I brand) on the road" Novosibirsk - Irkutsk ", km 45-60" The recipe must contain: Information about the applicable information mineral materials, grain composition of the mixture (with division into components and without it), a binder; production recipe; Indicators of the properties of the mixture and asphalt concrete; Data on consumption of materials. The norms of difficulty losses taken into account in the recipe must be indicated. For installations of type DS-117, DS- 158, the loss rate for an ABZ is 1.5%, the loss rate when laying the mixture is 1.5% the recipe must be signed by the head of the laboratory that selection. If the selection is made by a third-party organization, the recipe signs its technical supervisor, the signature is assigned to the seal. 10. Approval and approval of the recipe for a asphalt concrete mixture used at the facilities of the "Kemerovo Dodph" facilities should be approved by the chief engineer (technical director) of the contracting organization and agreed by the Chief Engineer of the Customer (GU "Kemerovo Dodf"). If a contracting organization acquires a mixture of a third-party organization, it is obliged to seek the mixture of the recipe, agreed by the Cemerovo Dodph Statement before coordinating the recipe for the customer, he must pass an examination at the Kuzbass Center for Road Research Center. Examination must be carried out on time not more than 5 working days. In the process of examination, the recipe compliance with the requirements of SNiP, GOST 9128, the correctness of its design and calculation of the mixture composition is estimated. The compliance of the physicomechanical and other indicators of the mixture specified in the recipe, the actual values \u200b\u200bare monitored during the technical supervision of the Customer, the Contractor is responsible for the accuracy of the information presented in the recipe, and the compliance of the recipes used by the mixtures is obliged to consider the recipe for 5 days. If the recipe went to the coordination procedure, one copy remains at the Customer, one copy is sent to the Contractor and the Organization that carries out independent control. In case of refusal in coordination, the Customer sends a contractor recipe. The failure must be motivated. After the appropriate adjustment, the recipe is again undergoing the coordination procedure provided for by this standard for refusing to refuse the recipe: - the recipe has not passed the examination; - non-compliance with the requirements of regulatory documents and (or) of the project;
13 - Non-compliance with the requirements of this Standard. 11. Inspection control over compliance with mixtures recipes Inspection control over compliance with the recipes of asphalt concrete mixes is carried out by the Customer's technical supervision service engineers, an independent competent organization (on the instructions of the Customer), the administration of the organization producing a mixture or using it. Coordinated chief engineer KDDF A.S. Belokobylsky 200 g. M.P. Approve the chief engineer 200 g. M.P. The recipe for an asphalt concrete mixture for the device (type and type of brand) (upper / lower / coating layer, base) on the road with PC (km) on PC (km) Material name, 1. Used mineral materials Private residues (the number of grains,% by Mass remaining on sieves with cell size, mm)
14 Manufacturer or quarry Name of material, 5 1.25 0.63 0.315 0.14 0.071 Mene E 2. Grain composition of the asphalt concrete mixture 2.1. With division into components, the content of private residues (the amount of grains,% by weight remaining on the sieve with the size of the cells, mm) in a / b, 5 1.25 0.63 0.315 0.14 0.071 mene of the mixture, e% 2.2. Without division into components, private residues,% full residues,% passes,% grain composition of the mineral part of the mixture according to GOST,% 3. Knitting,% over 100% mineral part 3.1. Bitumen (brand, manufacturer) content in a binder,% 3.2. Modifier (name, brand) Contents in a binder,% 3.3. Solvent (name, brand,) Contents in a binder,% binder or fraction of stone materials in accordance with hot bunkers ABZ 4. Composition of the asphalt concrete mixture Dosage on the kneading mass, kg binding or fraction of stone materials in accordance with the hot bunkers of the ABZ dosage to the brave weight, kg Name of indicators 5. Indicators of the properties of asphalt concrete according to GOST actually the name of the GOST actors
15 1. Average density, g / cm 3 6. Water resistance with long-term water saturation 2. Porosity of mineral part,% by volume 3. Water saturation,% by volume 4. Screenshot strength (MPa) at: 20 s 50 s 0 s 5 . Water resistance 7. Bitumen grip with mineral part of the asphalt concrete mixture 8 *. Exchange rate 9 *. Fragment resistance rate 10. Total specific effective activity of natural radionuclides The test withstands * These indicators are defined if they are normalized by the project documentation for the construction of the coating 6. Material consumption of bulk density, T / M 3 t content Name of material in the mixture,% m 3 per 100 t BC / kg per 1000 m 2, the coatings of the asphalt concrete mixture (T), with a layer thickness of 4 cm when the layer thickness change is changed by 0.5 cm, add the table is drawn up taking into account the rule of loss of% per para and% when laying the mixture. Head of the selection by the selection agreed by Cuzzdi
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