Technological description
1. TECHNOLOGICAL PROCEDURE
Remedial work can be carried out at air temperatures above 0 °C and the air temperature in last 24 hours would not be lower than -5 °C. In exceptional cases if there is a requirement to remove failure of road practicability, it is possible to carry out remedial work also at minus air temperatures, but it is necessary to modify technological procedure so to observe the compacting temperature of the asphalt mixture min. 130 °C. The road surface has to be always dry or only slightly damp. Remedial work cannot be carried out in rain or snowfall. Remedial work cannot be carried out if the pot-hole is filed with water.
1.1 Preparation work
1.1.1 Representatives of the customer and the maker specify work extent before its start, with regard to the current condition of the road.
1.1.2 It is necessary before beginning of work to verify that the repairing place has the failure cause only in the repairing course and not in the lower laid layer (layers) or even in the road bed.
1.1.3 Working area is delimited by placing of traffic signs or traffic devices. Remedial work is usually carried out with running traffic, with its partial limitation. Location of the traffic signs has to be discussed and approved in advance (see point 9.3.2).
1.1.4 Before remedial work is executed, the road surface is properly cleaned from earth, dust and other dirt (by sweeping, jetting with pressure air).
1.2 Work performance itself
1.2.1 Thickness of the original wearing course (or possibly the wearing and also partly the base course) of the road has to provide the thickness needed for recycling. In case a part of the base course could be recycled together with the wearing course, the condition of original wearing course does not need to be met and the construction mixture of both courses could be recycled in one working cycle. However it is limited only to overland communications of lower traffic importance.
During working procedure has to be avoid overburning of the old asphalt binder in recycling material and the road has to be heated into such a depth that the temperature of the recycled mixture reaches the required temperature. It is recommended to perform heating into a thickness of 2030 mm. Further it is necessary to match up working time of heating, gas pressure in infra-red radiators, their height above the road. Working on a damp covering, with cold and windy weather creates higher risk of uneven heating of the whole thickness of the processed course.
Too high temperature of infra-red radiation is characterized by strong smoke generation, the low temperature by mechanical damage of aggregate grains with material destruction of the original road course. For this reason it is necessary to perform continuous temperature inspection with a manual thermometer. Cross and longitudinal connection to the existing road layer is secured by heating of the original road covering from both sides in the width min. 10 cm larger than the working pot-hole width.
Amount of additional R-material is done by a geometric shape of the road surface (pot-hole depth, profile levelling in the place of road depression) and by wear of the wearing course due to material loss (depth corrosion).
1.2.2 R-material preparation
R-material is located and heated in the SILKOT device according to corresponding producer's manual for device operation. The operation consists of addition (feeding) of milled-off or pre-crushed R-material in a required volume.
1.2.3 The treated pot-hole up to a depth of max. 55 mm will be filled with R-material. Levelling of recycling material to the road profile is carried out with wooden or metal stirring arms with a required superelevation of ca 20-30% of the layer thickness.
To keep the required superelevation in the whole area and especially at edges and corners, it is recommended to use bordering laths or balks so to enable mixture levelling with a smoothing lath.
The temperature of the recycled mixture with stirring depends on penetration of the asphalt binder and it is stated in Table 1.
Table 1: Operation temperatures of recycled mixture
| Penetration of final binder of recycling material | Mixture temperature (°C) | |
| MIN | MAX. | |
| > 100 | 125 | 160 |
| 66 – 100 | 130 | 165 |
| ≤ 65 | 145 | 180 |
1.2.4 Compaction of the spread and levelled mixture is executed with manually driven vibratory rollers. It is proceeded in direction from working joints. Compaction with vibrating plates or other devices is not recommended.
Compaction is carried out immediately after mixture levelling, while this is still hot, and so long until the surface of remedial work is flat, compact and without marks of a compacting machine. The surface of remedial work must be in one level with the surrounding road surface.
Place of remedial work could be powdered with fine-grained spreading.
1.3 Finishing work includes cleaning of the workplace, removal of traffic signs, carrying away of machinery and working aids, and release of the road for traffic. The road release for traffic is recommended only after mixture cooling to the temperature lower than 60 °C.
2. WORK ACCEPTANCE, TESTING AND INSPECTION
For work handover and takeover provisions of TKP, Chapter 7 – Appendix no. 2 – Maintenance and repairs of compacting asphalt layers are valid.
Work maker proves capability to carry out work, e.g. in accordance to Methodical Instruction to Quality System in Area of Overland Communications (SJ-PK). It is recommended to submit references that the same work has been already carried out by him in the past.
The obligation to prove capability is valid for a professional laboratory – a processor of a job instruction further in accordance with the Methodical Instruction to SJ-PK for Part II/3 Testing (laboratory activities).
2.1 Type tests
For local remedial work the type test of the asphalt mixture must not be approved by the customer.
2.2 Check tests
By this straightness, void fraction, rate of compaction (at core holes or non-destructively) of the finished asphalt layer is proved in frequency defined by the customer.
2.3 Work handover and takeover is executed by authorized personnel of the maker and the customer. At acceptance following is checked:
- Integrity of the remedial work surface,
- connection tightness in working joints,
- surface straightness according to ČSN 73 6175; to evaluate straightness of local remedial work of asphalt layers a tolerance of 8 mm is valid; in case of customer requirement at communications of higher traffic importance the maximum permissible tolerance is 5 mm,
- records of performed laboratory tests and volume of build-in materials.
3. WORK SAFETY AND HEALTH PROTECTION
3.1 General rules of work safety and health protection
Workers are required to observe at work general rules of work safety and hygiene and to use prescribed protective equipment.
At handling with asphalt materials it is necessary to observe relevant provisions of work safety.
3.2 Operators of the SILKOT device and other machines must be provably trained in their operation (according to producer's instructions) and their knowledge must be verified practically. They have to have relevant certifications for machine operation.
3.3 Work safety during road traffic
3.3.1 Safety of workers
At work with road traffic the workers have to be equipped with warning cloths with marking of retro-reflective material with high visibility.
The towing car and the SILKOT device have to be provided with warning beacons of orange colour and they have to be operated constantly during work.
3.3.2 Safety of road traffic participants is secured by traffic regulation by means of a system of vertical traffic signs and traffic facilities.
It is a temporary arrangement of traffic on overland communications according to provisions of §61 par. 4 of Act no. 361/2000 Coll.
Rules for temporary traffic signs on overland communications are specified in TP 66 MDS CR. However the required base for their application to specific cases are provisions of Act no. 361/2000 Coll. as amended and the implementing regulation – Notice of Ministry of Transport of Czech Republic no. 30/2001 Coll. as amended, especially as for a location and a kind of traffic signs.
3.3.3 Rules for work safety on motorways and main roads, of which management the Road and Motorway Directorate of CR is responsible, are specified by the General Manager Regulation no. 2/02 – Rules of work safety on motorways and roads with traffic.
4. ENVIRONMENTAL PROTECTION
During work execution the maker is liable to act so that no risk of environment damage occurs and that all regulations related to environmental protection are observed.
5. QUOTED AND RELATED STANDARDS AND REGULATIONS
| ČSN EN 12591 | Asphalts and asphalt binders. Specifications for road asphalts. |
| ČSN EN 1427 | Determination of softening point. Ring and ball method. |
| ČSN EN 13108-1 | Asphalt mixtures – Specifications for materials – Part 1: Asphalt concrete |
| ČSN EN 13108-8 | Asphalt mixtures – Specifications for materials – Part 8: R-material |
| ČSN EN 13108-20 | Asphalt mixtures – Specifications for materials – Part 20: Type tests |
| ČSN 73 6100 | Road terminology |
| ČSN 73 6121 | Construction of roads – Compacted asphalt layers – Execution and check of compliance |
| TP 66 | Rules for temporary traffic signs on overland communications |
| TP 82 | Catalogue of failures of non-rigid roads |
| TP 87 | Designing of maintenance and repairs of non-rigid roads |
| TP 105 | Disposal of waste resulting from construction, repair and maintenance of overland communications |
| TP 150 | Continuous maintenance and repair of roads of overland communications containing tar binders |
| TP 208 | Recycling of construction courses of non-rigid roads in cold way |
| TP 209 | Recycling of asphalt layers of non-rigid roads in-situ in hot way |
| TKP Kap. 7 | Compacted asphalt layers |
| SJ-PK | Quality system in area of overland communications (SJ-PK) ref. no. 20840/01-120, from 10.4.2001 (Traffic bulletin 9 from 2.5.2001) as amended by changes ref. no. 30678/01-123 from 20.12.2001 (Traffic bulletin 1 from 10.1.2002), ref. no. 47/2003-120-RS/1 from 31.1.2003 (Traffic bulletin 4 from 19.2.2003), ref. no. 174/05-120RS/1 from 1.4.2005 (Traffic bulletin 9 from 27.4.2005) and ref. no. 678/2008-910-IPK/1 from 1.8.2008 (full version including repair of printing errors was announced under ref. no. 678/2008-910IPK/2 in Traffic bulletin 18 from 27th August 2008) and change ref. no. 980/2010-910-IPK/1 from 9th November 2010. |
Act no. 361/2000 Coll. about traffic on overland communications
Notice of Ministry of Transport no. 30/2001 Coll., by which rules of traffic on overland communications and adaptation and control of traffic on overland communications are implemented.
