Technical description

1. INTRODUCTION

Technologies performed in the scope of a routine maintenance of roads of overland communications of other traffic surfaces are necessary tools for preservation of serviceability in a required level. In many cases, the surface technical conditions are not worsened continuously in a full area but degradation occurs only locally from various reasons. So it is necessary to remove the defect operatively for safety reasons of road traffic. In most cases, the local maintenance has a feature of a temporary measure.

The term road recycling can be defined as use of materials from the original road that are reused in the road structure in the way suitable technically and ecologically. In case material from the original road is again used in the same place of the road structure without carrying away, it is recycling in-situ.

With recycling can be achieved:

• efficient use of wastes through their transformation to recycled material instead of their disposal to controlled waste dumps,
• limitation of exploitation of natural resources,
• energy saving,
• decrease of some of undesirable influences (noise, pollution, construction time, etc.).

Asphalt road layers composed of a mixture of aggregate coated with asphalt binder can be recycled successfully. With optimal recycling technology the final quality of the structure with used a layer (layers) of recycled materials would not differ from the quality of the road made of only new materials. In case of use of recycled materials in the scope of the routine maintenance of roads in critical or unsuitable condition the remedial work is always of short time nature due to occurrence of construction failures.

 

2. SUBJECT

This technical regulation contains general rules for execution of the routine maintenance of compacted asphalt layers with repeated treatment of the original asphalt mixture in a hot way in-situ; this is performed by its melting with the SILKOT device, addition of asphalt R-material, manual mixing and machine compaction.

The regulation does not include recycling of bituminous material, i.e. material that contains tar fully or partly instead of asphalt, or possibly other binders polluting the environment. It is necessary to apply special technologies and working procedures for maintenance and repairs of roads with tar, which are removing or at least limiting this environmental strain. In case of tar occurrence, it is required to follow TP 150.

With regard to time limited practical experience with application of the SILKOT device and with evaluation of resulting remedial work in Czech Republic, this regulation is created as preliminary. More substantial investigation of this technology has not been accomplished. Therefore device users, communication administrators and professional public ask for providing of practical experience first of all with the resulting quality of executed remedial work to e-mail address info@siltek.cz.

 

3. TERMS AND DEFINITIONS

3.1 As remedial work according to this regulation a local repair of road covering with use of a hot asphalt mixture is understand. Remedial work are especially repair of pot-holes in the wearing course or in the whole road covering, exceptionally repairs of a local depression (e.g. after excavations and cross-cuts). Remedial work is mostly carried out as a completed surface treatment of the wearing course in the place of damage. Remedial work solves current problem of a pot-hole by its removal.

3.2 Recycling in-situ in a hot way (in the sense of this regulation) is repeated processing of an asphalt mixture in the build-in place with replenishment of missing mixture amount with heated additional asphalt R-material.

3.3 Recycling material in the sense of this regulation is an asphalt mixture in the place of remedial work acquired by heating and disconnecting from the original compacted asphalt layer, usually from the wearing course.

3.4 R-material is a homogenized mixture of aggregate and asphalt acquired by milling from covering road layers or by destroying, crushing and sorting, and it is determined for further use, especially in technologies of hot recycling. Material of better quality is obtained by separate milling of the wearing course and the base asphalt course.

 

4. BUILDING MATERIAL

4.1 Recycling material (material of the original road structure) is basic construction material. A building mixture of the recycled layer has to meet requirements of a maximum grain size corresponding to the thickness of the resulting layer. In most cases recycling material is used only from the wearing course of the road.

4.2 R-material (added asphalt mixture)
Grain-size composition of the added asphalt mixture should comply with requirements for asphalt concrete for wearing courses of ACO 11 or ACO 16 type. Verification will be carried out by a separate laboratory analysis.

4.3 Recycled asphalt mixture
The resulting mixture of remedial work composed of recycling material and R-material.

 

5. CONSTRUCTION MACHINES

5.1 The special device SILKOT 70-80 for remedial work of compacted asphalt layers is a mobile device for melting of asphalt material of the original road structure layer in the place of remedial work execution by infra-red technology. The device is also equipped with a container for storage and heating of asphalt R-material. The device is not provided with possibility of forced stirring of this R-material.

The SILKOT device is pulled by a tractor or it is located on a lorry and it is equipped with infra-red radiators located in a rear warming-up hinged face, and as well with an insulated heating container of R-material.

Work with the SILKOT device is included in a flow of partial technologic procedures for execution of remedial work as a key procedure.

5.2 Machinery for remedial work technology with use of the SILKOT device:

• SILKOT device
• tools and aids for manual stirring and levelling of a heated recycled mixture and R-material
• compacting device: a small manually-driven vibratory roller

 

6. TREATMENT OF RECYCLED ASPHALT MIXTURE

6.1 Laboratory preparation is recommended only for work of larger extent at a homogenous section on communications with more important traffic and/or in cases when it is required by the customer of this routine maintenance technology.

6.2 If point 6.1 is applied, the laboratory with relevant professional authorization will create a proposal of recycled mixture treatment with additional R-material, based on laboratory analysis of mixture samples taken from places where remedial work is to be executed (core hole or cut-out) and of samples taken from the stock of R-material.

The sampling frequency depends on executed repair extent and possible qualitative changes of the road surface.

6.3 With core holes following is find out:

• thickness of the wearing course (or the wearing and the base course)
• volume weight
• void fraction
• aggregate grain size
• binder content

In case of tar occurrence, or other binders that are classified as danger substances from the viewpoint of environmental protection, this procedure according to article 2 cannot be used.

 

7. 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.