Diploma project for the reconstruction of the Osinovka-Rudnaya pier highway section (175-184 km)

Contents

CONTENTS

 

 

Introduction

Justification of the need for reconstruction

road

National economic significance of the existing

roads. Economics. Transport

1.2 Justification of road section reconstruction

1. Z Characteristic of the road under construction

1.4 Calculation of prospective traffic intensity

1.5 Soil and geological conditions of the construction area

1.6 Characteristics of road building materials

Natural and climatic conditions of the construction area

Climate of the construction area

3. Determination of possible work execution dates

3.1 Road-climatic schedule of the construction area

3.2 Determination of possible terms of works execution and

minimum speeds of specialized detachments and work shifts per year

4. Technology and organization of works on construction of small bridges and culverts

4.1 Characteristics of small artificial structures

4.2 Calculation of labour intensity of works for repair and construction of small artificial structures

Design of squad composition and determination of number of squads for construction of small artificial structures

4.4 Technology of construction of small artificial structures

4.5 Organization of works on construction of small artificial structures

4.6 Quality control of works

4.7 Safety precautions for construction of small artificial structures

Technology and organization of works on erection of roadbed

5.1 General relief characteristic of the route. By picket count of excavation volumes

Determination of soil movement range. Selection of methods of erection of roadbed and leading earth-moving vehicles

5.3 Design of roadbed erection units

5.4 Refinement of the work rate. Determination of the number of leading machines and auxiliary machines in detachments

5.5 Technical and economic comparison of detachments

5.6 Technology of erection of roadbed

5.7 Clarification of the process sequence of erection of the roadway during reconstruction of the road

5.8 Organization of works on erection of roadbed

5.9 Quality control of works

5.10 Safety precautions during earthworks

erection of the roadbed

6. Technology and organization of construction works

road clothing

6.1 Roadway Construction

6.2 Calculation of Scope of Work

6.3 Design options for construction units

road clothing. Techno-economic comparison 

groups

6.4 Structural Construction Process

layers of road clothing

6.5 Organization of works on construction of structural layers of road clothing

6.6 Quality control of works

6.7 Construction Safety

structural layers of road clothing

7. Cost-effectiveness rationale

investment project

7.1 Determination of estimated project cost

7.2 Calculation of economic efficiency

investment project

7.3 Conclusions

8. Occupational Safety and Safety

road construction

Selection of asphalt concrete composition and 

improving its quality

9.1 Asphalt concrete

9.2 Selection of asphalt concrete composition

9.3 Quality control of asphalt concrete

9.4 Ways to improve the quality of asphalt concrete

Conclusion

List of sources used

Introduction

The purpose of this graduation qualification work is to develop a project for the technology and organization of the reconstruction of the Razdolnaya-Hassan highway (1218 km). To achieve this goal, the following tasks are defined: to determine the required scope of work for reconstruction, taking into account the terms of work, to select and feasibility study the use of road construction machines with the formation of detachments, to calculate the cost of the facility, to work out safety, health and environment issues.

In the final qualification work, modern methods of organizing work are used. Works are performed in-line. In one year of reconstruction, both the erection of the roadbed and the construction of road clothing are carried out. The presented draft consists of an explanatory note in which all the above listed tasks and drawings of A1 format with diagrams and drawings on nine sheets are discussed.

Substantiation of the need for road reconstruction

1.1 National economic significance of the existing road. Economics. Transport

The reconstructed section of the Osinovka-Rudnaya marina road (175-184 km) is located in the Chuguevsky district of Primorsky Krai. In the construction area, a rather developed network of roads of federal and local importance. Rail and air transport has no effect on the load tension of the designed road. The implementation of the entire volume of intra-district and most inter-district transport links in the area of ​ ​ gravity of the reconstructed road is carried out by federal and local roads. The main direction of the reconstructed section of the Osinovka-Rudnaya pier road is the provision of passenger transport, as well as the transportation of construction goods. Due to the increasing pace of development of the region's economy and the increase in the number of freight transportation by road, the development of the road network is a primary task. This is due to a decrease in freight turnover in rail transport and an increase in transportation tariffs, as well as an increase in the total number of cars and, accordingly, traffic intensity on the existing road network.

The economy of the region is pronounced industrial in nature. In the inter-district division of labor, the region's economy specializes in the fishing industry, non-ferrous metallurgy, the forestry and woodworking industries, and fur harvesting. Mechanical engineering, metalworking, the fuel and energy industry, the production of building materials, the chemical and food industries also play an important role. In the fuel balance of the edge, the first place belongs to coal. Primorsky Krai is one of the largest fishing areas in the Far East. The fishing industry produces about 1/5 of the gross output of the region's industry. The main branches of non-ferrous metallurgy are tin and lead-zinc. The chemical industry includes mining and chemical plants and a number of other enterprises.

Rail transport is predominant among existing modes of transport, accounting for about 80 per cent of all freight traffic. A railway passes through the territory of the region. Air communication is well developed. The role of maritime transport is great. Through the ports of Nakhodka, Vladivostok, communications are carried out with the islands of Sakhalin, Kuril Islands, the Okhotsk coast, Kamchatka and Chukotka, as well as import and export transportation. The main roads in the region - Khabarovsk-Vladivostok and Khabarovsk-Nakhodka are both federal and strategic. There is a network of local roads on which domestic traffic is carried out.

1.2 Justification of road section reconstruction

An increase in traffic intensity with a subsequent decrease in throughput leads to the fact that the road is congested, "traffic jams" are formed in certain sections. The speed of the car decreases. This leads to an increase in the cost of transportation, wear and tear of vehicles. The parameters of the road do not satisfy the intensity and composition of traffic, so it is necessary to expand the roadway of the roadway, increase the radius of curves and longitudinal slopes. Only an improvement in transport and operational indicators will increase throughput and reduce the cost of transportation.

1.3 Characteristics of the road under construction

In accordance with the prospective traffic intensity of 1100 autos/day, defined in the working design, and guided by paragraph 4.20 of SNiP 2.05.0285, the reconstruction of the highway is designed according to the norms of the third technical category, which are given in Table 1.1. Artificial structures - capital for design loads A11, NK-80. The length of the road section is 9 km, the general direction of the route is northeast. An exquisite section of the route runs throughout the existing highway. All angles of rotation are due to the inscription of the route into the earthwork of the existing highway. The number of rotation angles 6, minimum radius 1000 m, is designed in constrained conditions. The route is fixed as planned by typical wooden columns, metal signs and bridges on trees. In terms of height, the route is fixed with temporary wooden turnpieces. Currently, the existing highway on the 175-184 km Osinovka-Rudnaya pier section does not meet the parameters of the III technical category. It has an unstable earthen bed, filled with loam with an admixture of gravel from 10 to 30 percent, 810 m wide, 6 m wide carriageway. Sickle-shaped roadwear of a lower type, the coating is black, the shoulders are reinforced with gravel, drainage is provided through reinforced concrete pipes.

1.5 Soil geologic conditions of construction area

The ground-geological state of the site is marked by a complex structure and is characterized by the presence of alluvial, deluvial and eluvial formations. Eruptive rocks are also widespread, and on the uvals overlook the daytime surface. Under the bottoms of the valleys, eruptive rocks are submerged to a significant depth. The vegetation layer is 0.20 meters. In the channels of watercourses, the upper layer is silted sandy loam up to 1.4 meters.

1.6 Characteristics of road building materials

 According to the conditions for obtaining local road construction materials, the area of ​ ​ the route is unfavorable.  There are no industrial enterprises whose waste can be useful in road construction in this area.

The working design uses the list of sources of obtaining road construction materials issued by the customer.

Wood soil of group V is used to fill the roadbed. The soil deposit is located on 181 km of the Osinovka-Rudnaya pier highway to the right 0.6 km, it is composed of granitoparfits.

Physical and mechanical properties of the tree: 10 mm -13.7 percent; 5 mm - 8.4 percent; 2.5 mm - 7.1 percent; 0.14 mm - 15.3 percent; 1.25 mm - 13.4 percent; 0.63 mm - 15.8 percent; 0.314 mm - 22.7 percent; less than 0.4 mm - 36.9 percent.

The construction of the access road to the quarry is not required.

For the construction of road clothing use:

for an additional layer of the base - ASG from a quarry of 178 km of the Osinovka - Rudnaya pier highway, 1 km to the left;

for the base layer - crushed stone from the quarry of Novomikhailovka;

for the coating layer - asphalt concrete with ABZ on the Osinovka - Rudnaya pier highway 175 km, 0.9 km to the right.

Physico-mechanic

2 NATURAL AND CLIMATIC CONDITIONS OF CONSTRUCTION AREA

2.1 Climate of the road construction area

The road design area is located in the second road-climatic zone and according to SNiP 2.001.0182 to the first climate subdivision and is characterized by a monsoon continental climate, with mild winter and warm wet summers. The average January temperature in the south of the region is -22 S, and the average July temperature reaches 21 S. In the southern regions of the region there is from 600 to 800 mm of precipitation per year. Maximum precipitation falls in the summer period. The growing season in the south of the region ranges from 170 to 180 days. Average monthly air temperatures are given in Table 2.1. For the design area, the average annual air temperature is 2.5 S. The temperature regime is mainly due to the nature of atmospheric circulation and terrain. Continental climate has a significant influence, which is manifested in a pronounced difference between winter and summer air temperatures. The duration of the period with average daily negative air temperatures is 163 days. According to SNiP II781, the first area under consideration is classified as non-seismic.

The absolute minimum temperature of the design area is 43 S, the absolute maximum is 39 S.

The estimated level of snow cover for the conditions of Primorsky Krai ranges from 0.10 to 0.25 m. The volume of snow transfer in the south of the region is 100... 200 m3/m. Snowy steady cover has been observed since mid-November. Snow cover reaches its maximum value in February. The descent of snow cover is noted by the first half of April. Below, in table 2.2, are the average snow cover heights by month. The maximum height of the snow cover in the design area is 40 cm. The average maximum freezing depth of clay and loamy soils, sandy soils and sands is 150 m3/m. The number of days with a temperature above 0 S - 214. The annual rainfall is 633 mm. The distribution of precipitation by month is shown in the table. 2.3. The remaining climatological indicators according to [46] are given in Tables 2.3 - 2.7.

The repeatability of wind directions relative to the light points for the warmest and coldest month is given in Table 2.7. A crucial role in the nature of the wind regime is played by the general circulation of the atmosphere reflecting the monsoon nature of the climate. In conditions of rough hilly terrain, the wind near the ground emphasizes the influence of valleys and mountain ranges, which is associated with the deformation of air flows under the influence of the relief. Figure 2.1 shows the roses of the January and July winds.

Determination of possible work execution dates

3.1 Road-climatic schedule of the construction area

According to climatological indicators (tables 2.1 - 2.7), a road-climatic schedule of the Osinovka-Rudnaya pier highway reconstruction area in the Primorsky Territory was developed.

3.2 Determination of possible terms of works, minimum speeds of specialized detachments and work shifts in a year.

Possible terms of works execution and minimum terms of works execution are specified in Table 3.1.

Construction of artificial structures and concentrated earthworks can begin from the beginning of the year, taking into account weekends and holidays. We accept the start date of these works on January 5th.

The additional base layer can be started at a temperature of 0 C in spring, i.e. 30 March.

The construction of the crushed stone base can also begin on March 30, but on this day previous work begins on the construction of an additional base layer. Therefore, it is necessary to establish an initial technological reserve of four days, that is, the start of work on the construction of the foundation - April 4.

Asphalt concrete coating can be started in spring at 5 S, i.e. 30 April (see table 2.5). Taking into account the technological dependence between the work of four days, the construction of asphalt concrete pavement can begin on April 7. We accept the commencement date for the coating arrangement on April 15th.

Work completion dates should be assigned according to the line schedule from the last work to the first. The laying of asphalt concrete should be completed at a temperature of 5 S, September 30. The date of completion of the previous work is set to 4 days earlier or for the time of collection of the necessary strength by the material. Completion dates are located in column 3

Technology and organization of works on construction of small bridges and culverts

4.1 Characteristics of small artificial structures

Characteristics of artificial structures are given in Table 4.1. Roadway design is assigned according to [6] and working design.

4.4 Technology of construction of small artificial structures

During the reconstruction of the Osinovka-Rudnaya pier highway section (175184 km), the old ones are repaired or new artificial structures are built. reconstruction of old prefabricated pipes consists of the following cycles:

The first cycle is preparatory work and dismantling of old heads, digging pits for new artificial structures.

The second cycle is the assembly of foundations and pipes with caps (inlet and outlet).

The third cycle is the device, waterproofing and filling of pipes.

The fourth cycle is the strengthening of the channel and the slopes of the embankment.

All works included in each cycle are performed by a separate specialized team equipped with the appropriate tool, equipment and mechanisms (machines).

Preparatory works include clearing and planning of the construction site, installation of equipment and arrangement of material warehouses, as well as delivery of pipe elements to the construction site.

Dismantling of old heads is carried out using bulldozers, and if the heads are prefabricated, then using a crane.

The pit for the foundation of the pipe and heads is torn off using an excavator.

If the pipe is installed on the foundation of blocks, then it is assembled in accordance with the layout diagrams. Rows of blocks are arranged horizontally within each section. Pipe slope is provided by stepped arrangement of sections. Assembly begins with laying of foundation blocks under pipe heads.

During construction of fundless pipes upper layer of soil is cut and crushed stone-sand cushion with profiled surface is arranged under pipe link.

Proposed device consists of bitumen primer and two layers of bitumen mastic. Pipe waterproofing shall be performed in dry weather at temperature not lower than 5 S.

After waterproofing the pipe is filled with soil. You can fill the pipe with soil, which is recommended for embankments or sandy soil with uniform layers with a thickness of 1520 cm with careful compaction of the lower layer.

Strengthening work is carried out by a specialized team after filling and at positive air temperatures.

4.5 Organization of works on construction of small artificial structures

Organization of works on repair and construction of small artificial structures is recommended to be carried out in summer time or at low negative air temperatures [8].

To draw up a project for the organization of work on the repair and construction of artificial structures, it is necessary to have a reconstruction schedule and a time frame for the construction of a highway.

In order to ensure that earthworks are not ahead of the reconstruction of artificial structures, we begin the reconstruction of the highway on January 5. Since the work is carried out in the cold season, the issue of water drainage for the reconstruction period is not considered. The linear planning chart shows the flow movement through the construction of artificial structures. The construction of culverts begins at the end of the reconstructed section.

Reinforced concrete products are supplied by transport from the Ussuri landfill of the IAS. The transportation distance is 246 km.

Reinforced concrete products are delivered to the place of work immediately before the start of construction of artificial structures in 1-2 days. Concrete and other building materials are delivered from nearby quarries and bases.

4.6 Quality control of works

Quality control during the reconstruction and construction of artificial structures is one of the important elements of the organization and management system. All aspects of the production and economic activities of the construction team for the reconstruction of artificial structures are subject to quality control.

During quality control, great attention is paid to concrete and reinforced concrete products coming for construction from production and other organizations. A lot of attention is also paid to internal quality control, which is carried out during the entire construction of an artificial structure and is carried out by the administrative and technical personnel of the construction organization. Special attention is paid to the timely execution and quality of hidden works, i.e. works, the quality and quantity of which cannot be determined in the future. Control of such works is executed by special acts.

4.7 Safety precautions for construction of small artificial structures

On the basis of the decisions taken in the project for the organization of work on the construction of artificial structures, as well as organizational and technical measures that take into account local conditions, current instructions and rules on safety and industrial sanitation, the contracting construction organization develops a project for the performance of work that ensures safe and harmless working conditions for workers.

During the construction of artificial structures, before the start of work, machine workers and machinists must be instructed, familiarized with the applied conditional alarm, supplied with gestures and flags, about the order of movement, maneuvering, places of turn, departures and exits, places of storage of materials, storage of equipment.

During the construction of blocks with sharp ribs, wooden gaskets must be inserted between the slings and the edges of the blocks, in order to avoid rubbing of the cables and damage to the structures.

It is necessary to pay attention to the safe operation of cranes, to strict compliance with the requirements imposed by the "Rules for the construction and safety of lifting cranes."

In the performance of all types of road construction works, timely provision of appropriate workwear, footwear and safety devices for workers and employees is important for safe working conditions.

Responsibility for timely provision of workers and employees with the above materials is assigned to the heads of road construction organizations.

5 TECHNOLOGY AND ORGANIZATION OF WORKS ON ERECTION OF ROADBED

5.1 General relief characteristic of the route. By station count of excavation volumes

The projected section of the route runs along hilly-weary terrain. The area of ​ ​ the route is flat and provided with a rather dense hydrological network. There are no significant inflections along the route on the earth's surface. The earth bed is designed taking into account the soil geological and hydrological conditions along the route. Cross profiles of the roadbed are designed according to [8]. On a larger section of the route, a waveless transverse profile of the roadbed with a slope of 1: 1.5 is designed. Drainage is carried out in longitudinal and transverse directions due to slope of terrain and reclamation watercourses. Excavation volumes are calculated on the PC according to the program "ZEMRAB" "Calculation of earthworks based on the design results of the longitudinal profile of the highway with the output of the calculation results to the file," depending on the category of the road, the type of the transverse profile of the road, the thickness of the vegetation soil, the coefficient of compaction and other factors.

5.6 Technology of erection of roadbed

We build an earthen canvas from a tree delivered by dump trucks from a quarry, where it is developed by two excavators EO5122.

Soil layer from the sides and slopes of the old embankment is removed and moved to the boundary of the diversion strip, and on valuable lands soil is stored on specially designated sites for this purpose. After removal of vegetal layer by bulldozer, soil is loaded into vehicles by excavators, taken out to areas reserved for folding and formed into stacks [9]. Ground dam base is compacted immediately prior to filling of overlying layers of earth bed or by means of road clothing. Soil in the quarry is developed by excavators after explosive loosening. For tillage using an explosive method, the method of spur charges is used. Development of penetrations by excavators in the face is carried out by sections along broken line [26]. The developed soil is transported by Kamaz-5511 dump trucks (10 tons) to a weighted average distance of 3.1 km. Soil is poured into the embankment from the edges to the middle in layers over the entire width of the roadway, including sloping parts. Each layer is leveled taking into account the longitudinal slope of the fill surface. In cross section, the surface of the layer is planned for a two-slope profile with a slope to the brow of 2040 ppm. The surface of each layer should be aligned so that after compaction there are no recesses or elevations on it more than 50 mm and that no puddles are formed during rain. When the newly erected embankment adjoins the old one, it is necessary to first fill the old cuvettes and layer-by-layer compact the filled soil in order to avoid roadway drawdowns due to unequal strength of the earthen dam. The degree of densification of backfilling of old cuvettes and other workings should be similar to the degree of densification of the widened fill at a given surface level. Compaction is performed in layers of 0.30 meters per 8 passes by one trace with DC26 roller. The layout of the top, bottom and slopes of the roadway and reserves is carried out by four passes of the DZ99 auto grader. Soil removed during slopes planning should be collected in stacks for movement to the shoulders and embankments. Cut soil, when accumulated, must not interfere with the drainage.

5.7 Clarification of the process sequence of erection of the roadway during reconstruction of the road

In view of the fact that in item 5.5 the technological sequence of erection of the roadway is determined without taking into account the reconstruction of the highway, we will compose a process map for the detachment defined in item 5.6, supplementing it with the technological operations required during reconstruction and noted in item 5.7.

5.9 Quality control of works

During the operational quality control [26], the erection of the roadbed is checked:

Place the centerline of the ground surface correctly in the plan

elevations;

thickness of the removable fertile layer;

soil density at the base of the earth bed;

humidity of the soil used;

thickness of soil layers to be filled;

flatness of the surface of the earth bed;

a transverse profile of the roadway corresponding to the design data;

homogeneity of soil in fill layers.

Permissible deviations are specified in Appendix SNiP 3.06.0385. Soil density is controlled in each process layer along the axis and at a distance of 1.52.0 m from the edge of the layer, and with a layer width of more than 2.0 m and gaps between them.

Soil density shall be controlled at least after 200 m at fill height up to 3 m and at least after 50 m at high fill height.

The density of the top layer of the embankment should be controlled at least 50 m later at a depth equal to 1/3 of the thickness of the compacted soil layer, but not less than 8 cm. Deviation from the required value of the compaction factor in the direction of decrease is allowed by not more than 10%.

Moisture control of the soil used is carried out, as a rule, at the place of its production at least once a shift and is mandatory during precipitation.

Soil density and humidity shall be determined as per GOST 518084. Accelerated express methods and instruments are allowed for monitoring.

The surface flatness of the roadbed is checked by leveling along the axis and eyebrows at three points across at least 50 m.

5.10 Safety precautions during earthworks

Excavation during the construction and reconstruction of the roadbed shall be carried out in accordance with the approved work organization project and the current production instructions, drawn up taking into account the requirements of SNIIA.11-70.

When performing rock, earth and other types of work, according to [13], related to the device (reconstruction) of the earth bed by explosive method, the requirements of the "Uniform Rules for Safety in Explosive Works" should be observed.

When operating bulldozers of all types, observe the following rules:

when moving the ground by a bulldozer on the rise, it is necessary to ensure that the dump does not crash into the ground; do not move soil by bulldozer to rise or slope more than 30 degrees:

dropping the ground under the slope by the bulldozer dump, do not extend the latter beyond the edge of the fill slope.

Do not stay between the tractor and the knife or under the tractor until the engine stops.

When turning the auto grader at the end of the profiled section, as well as at steep turns, the movement must be carried out at a minimum speed.

It is necessary to level the soil on backfilled embankments with a height of more than 1.5 m under the supervision of the responsible person. The distance between the edge of the roadbed and the outer wheels of the motor grader should be at least 1 m, depending on the specific conditions of production work.

Excavators shall be installed on a planned site during operation.

During excavator operation do not:

be the worker under his bucket or boom;

Carry out any other work on the side of the slaughter;

stay for unauthorized persons within the range of the excavator plus 5 m.

Loading of soil, crushed stone and other loose materials into the bodies of dump trucks shall be carried out in a position that prevents movement of the ladle over the car cabin. You can load from the rear or side side.

When loading dump trucks with excavators, the driver and other persons are forbidden to be in the cab of the car, which is not protected by a visor.

6 TECHNOLOGY AND ORGANIZATION OF WORKS ON ROADWAY CONSTRUCTION

6.1 Roadway Construction

Roadway design is assigned according to [6] and working design.

The type of pavement was developed on the basis of transport and operational requirements and the technical category of the designed highway, taking into account the composition, promising traffic intensity, climatic, soil geologic conditions, and availability of construction materials.

6.5 Organization of works on construction of structural layers of road clothing

Work on the construction of structural layers of road clothing is planned to be carried out by specialized flows.

The first stream is the arrangement of an additional base layer from ASG, with a rate of 65 m/shift.

The technological reserve with the previous flow must be at least 4 shifts.

 The second flow is the device of the base layer from fractional crushed stone according to the method of wedging.

The third stream - the arrangement of the coating layer of hot asphalt concrete mixture of grade II, is put into operation at a temperature of + 5 S in the spring, i.e. April 13.

The technological reserve with the previous flow must be at least 4 shifts.

Due to the fact that work on the construction of paving of road clothing can be carried out in the spring and autumn. We hold them from April 15 to September 30 with a shift rate of 65 m/shift.

Sprinkle shoulders are arranged after the construction of the coating, the speed of their installation cannot exceed the pace of previous work.

6.6 Quality control of works.

During the construction of road clothing, all elements are continuously monitored, checking the density, flatness, slopes and cleanliness during the coating arrangement, and when using side stops during automated laying, the correctness of their installation.

Temperature of asphalt concrete mixture is checked by thermometers or devices on the basis of infrared radiation assessment in each automotive vehicle that arrived at the place of laying. The mixture with reduced temperature is not taken and returned to the plant. The temperature of the asphalt concrete mixture should not be lower than 120 S.

Even and uniform distribution of asphalt concrete mixture, as well as the given thickness of the layer, taking into account compaction, take into account compliance with compaction rules. The check of evenness in the longitudinal profile is carried out after the rink, noting unsatisfactory places with chalk. All detected flaws are immediately eliminated.

After completion of works on construction of the coating, compliance of longitudinal and transverse profiles to the design is checked using leveler and templates, in accordance with technical codes, rules and instructions taking into account the requirements [3]. At large length of sections, flatness assessment is carried out with the help of PCRS2 device.

To assess the roughness of the coating, as well as the adhesion coefficient, special measurements are made. By moistening the coating in front of the bogie wheels, the wet coating adhesion coefficient is determined.

6.7 Safety precautions during construction of structural layers of road clothing.

Prior to commencement of construction of structural layers of road clothing, the section is enclosed and a detour is designed along which traffic is directed. Due to the work of asphalt laying machines, rinks, dump trucks and stone material distributors for workers, safe places of their work are outlined, as well as a scheme for entering and entering the work zone of stowers.

In the dark the place of work shall be illuminated with portable lamps and lamps. All workers must have standard workwear and shoes for work. Rollers shall be equipped with mechanical devices for lubrication of rollers. All mechanisms shall be equipped with an audio signal and shall be transmitted before the start of movement.

During operation of rollers and stowers for safety, the distance between them must be at least 10 m.

The engines of rollers and other machines can only include their drivers, complying with the relevant safety requirements.

In case of long interruptions in operation, asphalt liners and rollers are cleaned from remnants of the mixture, mechanisms are examined. Cars put on the brakes in one column. On both sides of the column of cars, fences with red signals are installed - during the day flags, at night - lanterns.

Workers and engineers are allowed to work after receiving training and checking knowledge on safety, fire protection and assistance.

Repeated briefing and check-up are carried out once a month.

Determination of estimated cost of road reconstruction

Source Data:

The territorial area of ​ ​ the construction of the highway is Primorsky Krai.

The technical category of the road is III.

Roadway construction:

top coating of dense fine asphalt concrete mixture - 5 cm;

lower layer of coating from porous coarse asphalt concrete mixture - 8 cm;

crushed stone base of 40-70 mm fraction, arranged by the method of wedging - 15 cm;

additional layer of base from natural sand-gravel mixture - 20 cm;

sprinkling shoulder from ASG - 28 cm.

The estimated cost of road works was calculated using resource and resource index methods. Summary and resource estimates for the construction of road clothing, resource statement for the construction of road clothing, resource estimate and resource statement for the construction of the roadbed, local calculation for preparatory work and strengthening of the roadbed, local calculation for artificial structures, local calculation for the construction of the road, estimated calculation for the rise in price in winter, calculation of transport costs for the transportation of local materials, calculation of the cost of materials

Selection of asphalt concrete composition and improvement of its quality

9.1 Asphalt concrete

Asphalt concrete is a road building material in the form of a compacted mixture of crushed stone, sand, mineral powder and bitumen in certain proportions, brought to a uniform consistency. Ratios of components constituting the mixture are determined by calculation in order to obtain dense, water-resistant and frost-resistant asphalt concrete capable of working in road surface. 15-20 years before overhaul.

Asphalt concrete properties are significantly influenced by the quality of sand added to the mixture. Asphalt concrete with crushed sand is more shear-resistant than with natural sand. Grains smaller than 0.071 mm contained in crushed sand should be considered mineral powder.

Depending on the laying temperature and viscosity of the bitumen used, asphalt concrete mixtures are divided into hot, warm, cold, cast and special purpose. Hot asphalt concrete is prepared on viscous bitumen of BND 90/130, BND 40/60 grades and laid in the coating at temperature not lower than 130 S. When surfactants are added to asphalt concrete, the mixture can be laid at 115 S. Warm asphalt concrete contains viscous bitumen of BND 200/300, BND 130/200 grades or liquid bitumen of SG 130/200. The laying temperature must be at least 80 S when using BND class bitumen and 60 S when using LG class bitumen. Hardening of hot asphalt concrete and its formation in the coating takes place within a short time - mainly after compaction and cooling of the mixture. Warm asphalt concrete, due to the presence of low-viscosity bitumen in it, is formed for a longer time. This allows you to lay it at lower temperatures and extend the construction time. Cold asphalt concrete is prepared using liquid bitumen of SG and MG type and laid in cold state at temperature not lower. This asphalt concrete is allowed to be laid at an ambient temperature of at least -10 S. In the process of preparing mixtures, complete dehydration of bitumen should be carried out and mineral materials should be dried well. The formation of cold asphalt concrete in the coating occurs gradually, under the influence of sealing loads from the wheels of moving vehicles. As the compaction progresses, the strength of the coating increases. However, in urban conditions, during the construction of asphalt concrete coatings, preference should be given to hot and warm mixtures with better physical and mechanical properties. Cast asphalt concrete is a type of hot asphalt concrete, in which all grain pores are completely filled with a binding component. Due to the increased ductility, there are practically no residual voids in it after laying and compaction. Such asphalt concrete during laying is not compacted, but only leveled and smoothed. Special-purpose asphalt concrete is characterized by any pronounced operational property - acid resistance (acid-resistant), which does not form sparks (spark-free), a certain color (color), etc.

Depending on the size of the grains of stone material, there are:

coarse grained asphalt concrete - with the largest crushed stone size of 40 mm;

medium-grained (20-25 mm);

fine-grained (10-15 mm);

sandy, the largest grain size is up to 5 mm.

The type of asphalt concrete is chosen depending on the nature of the traffic, the construction of the road surface, the available materials and the conditions for the work.

Coarse asphalt concrete is used only for the construction of the lower layer of asphalt concrete pavement, the rough and porous surface of which contributes to better adhesion to the upper layer. As a rule, coarse asphalt concrete is made porous, without mineral powder. In cases where the lower layer remains for winter without the upper layer, for greater safety, it is made of dense "filled" coarse asphalt concrete, to which the necessary amount of mineral powder is added.

Depending on the density, hot asphalt concrete is divided into dense with a residual porosity of 3-5% and porous, with a residual porosity of 5-10%, which is used only for the lower layer of coatings. Fine asphalt concrete provides high quality coatings and is used in heavy and heavy traffic. Fine asphalt concrete has sufficient resistance to shear forces acting on the road surface. The presence in asphalt concrete of a sufficient amount of shallow crushed stone of strong rocks gives the surface the necessary roughness to ensure good adhesion to the wheel of the car. These features of fine asphalt concrete have led to its widespread use for the construction of coatings on stressed roads. Sand asphalt concrete provides high quality road surfaces. Experience in the operation of asphalt concrete coatings shows that in terms of wear, as well as corrosion resistance to moisture, sand asphalt concrete is not only not inferior, but often superior to fine-grained. It is used for the construction of the upper layer of pavement of city and main roads.

9.2 Selection of asphalt concrete composition

9.2.1. Selection of grain composition of mineral mixture

One of the important factors ensuring the required quality of asphalt concrete is the grain composition of its mineral part. The latter should give optimal density of asphalt concrete, and if necessary - increased roughness. When appropriate materials (mainly coarse or medium sand) are available, it is recommended that the mineral part of asphalt concrete be selected according to the principle of continuous granulometry.

The mixture of crushed stone, sand and mineral powder is selected so that the curve of grain composition is located in the zone limited by limit curves and is as smooth as possible without sharp fractures.

Crushed stone should be strong cubic or tetrahedal in shape, due to which its fractionation during compaction and wear during operation is reduced. For the device of coating roughness , crushed stone from rocks of fine-grained crystalline structure is recommended during wear that retains the roughness of natural wear. The smaller the crushed stone grain, the higher the shear resistance of the asphalt concrete surface.

Mineral powder serves as an additive structuring bitumen and forming with it an asphalting substance that connects crushed stone and sand grains into a monolith. Mineral powder gives asphalt concrete adequate density, strength and heat resistance, and with excessive content in hot asphalt concrete causes an increase in brittleness and a decrease in deformability at low temperatures.

Excessive grinding of mineral powder (specific surface area more than 6000-8000 cm ²/g) increases its porosity, respectively, and the porosity of the mineral part of asphalt concrete (especially if the powder is more than 810%), which leads to increased bitumen consumption. High porosity of powders is characteristic of many powdered industrial wastes (dust, entrainment of cement plants, ash of CHP entrainment, etc.). Clay admixture in mineral powder significantly increases the ability of asphalt concrete to swell and reduces its water and frost resistance. At the same time, the lower the viscosity and bitumen content in asphalt concrete, the stronger the negative property of clay is manifested.

To improve quality, mineral powder is activated with a mixture of surfactant and bitumen. Asphalt concrete with activated mineral powder has increased strength, density, water and frost resistance.

In asphalt concrete with activated mineral powder, the bitumen content can be reduced by 1020% compared to asphalt concrete on unactivated powder.

The strength, water and frost resistance of asphalt concrete largely depend on the properties of the bitumen used. Viscous bitumen must have a complex of structural and mechanical properties: elasticity and ductility at low temperature, sufficient strength and heat resistance at high temperature, resistance against aging during processing and operation, strong adhesion to the surface of mineral materials. With the wet surface of mineral materials , the adhesion of bitumen is usually poor. The adhesion of bitumen to the surface of mineral materials, which affects the corrosion resistance of asphalt concrete, is increased by the introduction of surfactants or the use of activators.

The more viscous bitumen is used in asphalt concrete, the higher the strength of the latter. However, the excessively high viscosity of bitumen in hot asphalt concrete can lead to cracks on the surface.

Excess bitumen reduces strength, shear resistance and increases the ductility of asphalt concrete, which leads to the formation of shifts and waves on the coating in hot weather. Asphalt concrete with an excess of bitumen is characterized by a small amount of water saturation (less than 1%). The lack of bitumen reduces the strength, water and frost resistance of asphalt concrete. The lack of bitumen in asphalt concrete is evidenced by the large amount of water saturation.

9.2.2. Selection of asphalt concrete mixture composition

Fine-grained asphalt concrete mixture of type B of grade II for the upper layer of the coating consists of the following materials: granite crushed stone, sand and gravel mixture, screening, mineral powder and oil bitumen of grade BN 90/130, the properties of which meet technical requirements. Its grain composition is given in Table 10.1.

9.3 Quality control of asphalt concrete

9.3.1 Asphalt concrete mixture control at the plant

In the process of preparation of asphalt concrete mixture, the following are controlled: quality of materials, accuracy of dosing of mineral materials and bitumen, temperature mode of bitumen and asphalt concrete mixture preparation, duration of mixing of mineral materials with bitumen, temperature of finished asphalt concrete mixture, quality of finished mixture, compliance with its specified composition and requirements of GOST 912897.

If the properties of the raw materials change, the asphalt concrete mixture is adjusted as required.

Quality of materials used for preparation of asphalt concrete mixture is checked by methods established by appropriate standards. At the same time, crushed stone and gravel are characterized by crushing, wear in the shelf drum, degree of frost resistance. The quality of crushed stone is also assessed by the shape of crushed stone (by the content of hazel and undermolved grains), grain composition, by the content of pulverized and clay particles. For control, samples are taken from each fraction at least 1 times per 5 days and at the onset of new batches of crushed stone. In dubious cases, the brand of crushed stone, the number of weak grains, weathered and siliceous rocks are determined. These indicators are determined in accordance with GOST 826782.

Quality of ASG and screening is assessed by grain composition, coarseness modulus, dust and clay content in accordance with GOST 912897.

For control, samples are taken at least once every three days and when new batches arrive.

The quality of the mineral powder in each new batch is evaluated according to the properties normalized by GOST 1655778.

At current control  grain composition, moisture content of mineral powder, hydrophobicity and homogeneity of activated powder are determined once every three to five days. The current control determines the needle penetration depth at 25 S of viscous bitumen or the viscosity of liquid bitumen (standard viscometer). For this purpose samples are taken from each working boiler, and from continuous bitumen smelting plants  - once a shift.

Control of dosing of mineral materials from bitumen includes:

checking the operation of metering devices (at least once a month) and the accuracy of weighing mineral materials and bitumen, surfactants (twice a month);

 determination of bitumen content in asphalt concrete mixture by the method of accelerated extraction once every three to four shifts, as well as when the appearance of the mixture changes;

checking the grain composition of the mineral part of the asphalt concrete mixture after extraction of bitumen or calculating the mixture based on the grain composition of crushed stone, sand and mineral powder (once in three shifts).

With small changes in the grain composition of individual mineral materials (within  10%), the ratio of components is corrected. If the changes exceed the specified limit, a new composition of asphalt concrete mixture is selected; crushed stone content in the mixture is determined after bitumen extraction by the accelerated method once a shift. The grain composition of the mixture of types A, B, D intended for the device of coatings with a rough surface is determined at least once a shift by an accelerated method, as well as when the appearance of the mixture changes.

At control of temperature mode of bitumen and asphalt concrete mixture preparation temperature of asphalt concrete mixture and bitumen in boilers is measured every two - three hours.

In the process of preparing asphalt concrete mixture two-and-three times a shift, compliance with the set time of mixing material with bitumen is monitored.

9.3.2. Asphalt pavement control

During the coating arrangement in the first period of its formation the following is checked:

level, density and purity of the base;

the temperature of the hot and warm asphalt concrete mixture in each vehicle;

evenness and uniformity of distribution of asphalt concrete mixture, and given thickness of laid layer taking into account compaction coefficient;

sealing mode;

transverse and longitudinal slopes, systematic evenness of the coating during its construction;

careful arrangement of conjugations;

correct control of movement along the constructed section until the end of the process of forming a coating of cold (and in some cases warm) asphalt concrete mixture.

9.3.3.Technical quality control of finished coating

In the built coating, check:

compaction factor and layer thickness; adhesion strength of the layers to each other and to the base; compliance of asphalt concrete properties indicators with technical requirements; coating roughness parameters, traction factor of vehicle wheel with coating;

coating flatness, transverse slopes and layer thickness are checked according to SNII4078;

to control the quality of asphalt concrete, cores or cuttings are taken from the coating and tested in reformed and unformed states in order to establish the degree of coating compaction, as well as compliance of asphalt concrete properties with the requirements of GOST 912897.

Samples are taken on coatings from hot and warm asphalt concrete ten days after the coating device, and from cold - not earlier than thirty days after the coating device and the opening of automobile traffic on it.

If the thickness of the upper coating layer is less than 3 cm, the cores and cuts are taken together with the lower layer. Before testing, the top layer was carefully separated from the bottom layer with a hot knife. Cores and cutouts shall be taken not only from the middle of the lane, but also where the coating is less compacted by movement, as well as in the immediate vicinity of the coupling of the two strips. Samples are taken based on : with a coating width of not more than 7 m - three samples per 1 km, with a coating width of more than 7 m - three samples from every 7000 m ². At sampling thickness of layers is measured and strength of their adhesion between each other and base is visually evaluated.

9.4 Ways to improve the quality of asphalt concrete

When treating mineral materials (crushed stone, gravel, sand, mineral powder, etc.) with bitumen (tar) or other hydrocarbon liquid, new systems are formed that have a complex of physical and mechanical properties characteristic of coagulation-type structures. In turn, the physical and mechanical properties of such systems are determined by the physical and mechanical and physicochemical properties of the components included in the system: mineral (chemical-mineralogical composition, strength, size, particle shape, humidity, etc.) and organic - bitumen or tar (chemical and group composition, viscosity, heat resistance, etc.), their ratios and location in the mixture, as well as the nature of adsorption bonds formed during the interaction of bitumen (tar) with the surface of mineral material. At the same time bitumen (tar) and mineral materials must have certain physical and chemical properties that ensure sufficient strength, water and frost resistance, wear resistance of the structure when working in the surface or base of roads.

Requirements for materials must be selected based on the basis of physical and chemical processes that occur on the bitumen (tar) - mineral material phase division. The nature and intensity of the processes of interaction of contacting materials is determined by their molecular surface (physicochemical) properties and, first of all, free surface energy. The concept of surface energy of a solid or liquid (mineral materials, bitumen, etc.) can be obtained by considering the forces of interaction between internal particles of a substance (atoms, ions, molecules) and particles located on the surface of the material. Each particle of mineral material or liquid located inside the body experiences the action of attraction forces from all particles surrounding it, which are equal to zero. Particles located on the surface of mineral material (bitumen, tar, etc.) are subject to the action of attraction forces only from the side of particles located inside a solid body (liquid). The presence of unbalanced (uncompensated) elementary particles on the surface is equivalent to the fact that each elementary site of this surface has a certain amount of free energy equal to the work spent on the formation of a surface, which is called free surface energy or surface tension

All hydrophilic minerals have crystal lattices with an ionic (heteropolar) bond. Therefore, all stone materials, when crushed in the surface layer, have uncompensated (unbalanced) ions - ions with free valences. Acid rock materials have uncompensated oxygen ions that make up the tops of tetrahedra SiO4, which provides a negative charge to the surface. Materials from the main rocks have a positive surface charge due to uncompensated metal ions. Surface charges are especially pronounced in freshly crushed stone materials.

According to this, the surface of stone materials is well wetted with polar liquids: water, alcohol and poorly non-polar: oils and bitumen.

The ability of bitumen (tar) to wet and adhere to the surface of mineral material is due to the selective adsorption in the boundary layer of individual components of bitumen (tar) and, accordingly, the ability to reduce the free surface energy of the system.

Adsorption is an increase in the concentration in the surface layer of one of the components of the system, the presence of which reduces the free surface energy at the solid-liquid interface. The quantitative ratio between the adsorption value in the surface layer of the adsorbed substance and the change in free surface energy - surface tension is determined by the Gibbs equation

Conclusion

The diploma project "Reconstruction of the Osinovka-Rudnaya pier highway section in the Primorsky Territory from 175-184 km" was completed in full and in accordance with the task issued by the Department of "Roads" of the Far Eastern Road Institute (as part of the Khabarovsk State Technical University).

In the diploma project, in accordance with the goal and tasks set, all issues of reconstruction of the Osinovka-Rudnaya pier section of the highway in the Primorsky Territory were worked out and resolved.