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Impact of rigid pavements with the asphalt-concrete wearing course on road performance and traffic safety
Available online at www.sciencedirect.com Available online at www.sciencedirect.com
ScienceDirect ScienceDirect
Transportation Research Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com Transportation Research Procedia 00 (2018) 000–000
ScienceDirect
www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia
Transportation Research Procedia 36 (2018) 315–319 www.elsevier.com/locate/procedia
Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018) Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018)
Impact of rigid pavements with the asphalt asphalt-concrete concrete wearing course Impact of rigidon pavements with the asphalt asphalt-concrete concrete road performance and traffic safetywearing course on road performance and traffic safety a
Andrey Korochkin Korochkin* Andrey Korochkin Korochkin*
Moscow Automobile and Road Construction State Technical University (MADI), 64 Leningradskiy Prosp., Moscow, 125319, Russia
a
Moscow Automobile and Road Construction State Technical University (MADI), 64 Leningradskiy Prosp., Moscow, 125319, Russia
Abstract Abstract The article presents basic parameters of road pavements, affecting perfor performance mance of motor roads and traffic safety. Current design loads on thepresents structure, peculiarities of of their influence on the wearingperfor course are given. Pavement repair technologies, influ influence ence of The article basic parameters road pavements, affecting performance mance of motor roads and traffic safety. Current design various coursepeculiarities defects on of thetheir accident rateon arethe described. Prospects and advantages rigidtechnologies, pavement with asphaltasphalt loads onwearing the structure, influence wearing course are given. Pavement of repair influ influence ence of concrete wearing course course defects are provided with regard rate to traffic safety improvement improvement. various wearing on the accident are described. Prospects and advantages of rigid pavement with asphaltasphalt concrete wearing course are provided with regard to traffic safety improvement improvement. ©2018 The Authors. Published by Elsevier B.V. © 2018 The Authors. Published by Elsevier B.V. ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This is an accessPublished article under the CC BY-NC-ND ©2018 Theopen Authors. by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review review under responsibility theCC scientific committee of the Thirteenth International Conference on Organization and This is an open access article underof BY-NC-ND ND licenseof (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility ofthe the scientific committee the Thirteenth International Conference on Organization and Traffic Safety Management nagement in Large Cities (SPbOTSIC 2018) 2018). Peer-review review under responsibility of the scientific committee of Traffic Safety Management in Large Cities (SPbOTSIC 2018). the Thirteenth International Conference on Organization and nagement in Large Cities (SPbOTSIC 2018) 2018). Traffic Safety Management
Keywords:asphalt-concrete; cement-concrete; accident rate; traffic safety; strength; durability. Keywords:asphalt-concrete; cement-concrete; accident rate; traffic safety; strength; durability.
1. Introduction 1. Introduction As economy develops, transport flows on motor roads and highways increase. As a result, this leads to an increase in loads develops, on the pavement structure. Ever-increasing increasing represent increase. one of theAscauses of pavement As economy transport flows on motor roads loads and highways a result, this leadsdamage to an and deformation, deterioration of pavement performance performance. increase in loads on the pavement structure. Ever-increasing increasing loads represent one of the causes of pavement damage 2017 to the Russian Federal State Statistics Service data for 2017 (Federal State Statistics Service, 2017), performance. andAccording deformation, deterioration of pavement performance there are 1,408.8 thousand kilometers of motor roads in Russia, including 52 thousand kilometers of federal motor 2017 According to the Russian Federal State Statistics Service data for 2017 (Federal State Statistics Service, 2017), roads (Vasiliev, 2004). For comparison: the total length of motor roads in China amounts to 4,463.9 thousand . there are 1,408.8 thousand kilometers of motor roads in Russia, including 52 thousand kilometers of federal motor kilometers. ilometers. Resolution in the field of road construction only amounts extensiontoof4,463.9 the motor road roads (Vasiliev, 2004).. of Forissues comparison: the total length of motor implies roads innotChina thousand kilometers. ilometers. Resolution of issues in the field of road construction implies not only extension of the motor road * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000 000-0000 . * E-mail:[email protected] Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000 000-0000 .
E-mail:[email protected] 2352-1465© 2018 The Authors. Published by Elsevier B.V. This is an open access under the CC by BY-NC-ND license (https://creativecommons.org/licenses/by https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under 2352-1465© 2018 Thearticle Authors. Published Elsevier B.V. responsibility the scientific committee the Thirteenth International Conference on Organization and Traffic Safety Management https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under in This is an openofaccess article under the CCof BY-NC-ND license (https://creativecommons.org/licenses/by Large Cities (SPbOTSIC 2018). responsibility of the scientific committee of the Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018).
2352-1465 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018). 10.1016/j.trpro.2018.12.091
316 2
Andrey Korochkin / Transportation Research Procedia 36 (2018) 315–319 Andrey Korochkin / Transportation Research Procedia 00 (2018) 000–000
network but maintenance of the existing network in good operating condition. Basic road performance indicators (Dan et al., 2017) are as follows: 1. speed ensured by road conditions 2. traffic convenience and safety 3. traffic capacity and level of congestion 4. allowable axial load 5. total mass of cars 6. ergonomic, aesthetic and environmental properties of the road Road pavement is one of the main factors affecting traffic safety. Therefore, its structure shall provide the required technical characteristics during the entire design service life. Non-observance of the requirements to road pavements leads to an increase in the number of accidents. The purpose of the study is to determine a dependence of traffic safety on the road pavement structure and wearing course condition, as well as to define a method of accident rate decrease by means of various engineering solutions. According to the State Traffic Safety Inspectorate (2017), 13–18% of road accidents related to adverse road conditions are caused by wearing course unevenness (Nosov et al., 2017). Road accidents occur due to a sudden speed change (emergency braking), a maneuver in plan view or their simultaneous performance. The probability of collision increases sharply in case of same-direction and opposite-direction traffic. Moreover, road unevenness causes suspension vibrations which may result in the loss of control. Vibrations in trailers and semi-trailers of road trains lead to an increase in the dynamic corridor, thus increasing the probability of collision and loosing lateral stability (Konoplyanko, 1978). Uneven roads increase drivers' fatigue, distract their attention from other road objects, decrease traffic capacity and, finally, decrease vehicle stock efficiency. In such cases, traffic management methods provide warnings for road users. Besides high-quality road construction, the only efficient method of wearing course evenness control is timely repair. However, it should be noted that repair works on trafficways of road and streets also create high-risk areas and significantly decrease transportation efficiency due to the formation of pre-congestion and congestion conditions (Klekovkina et al., 2016). The article is based on studies of M-2 "Crimea", M-9 "Baltic", A-107 MSRR (Moscow Small Ring Road) motor roads and Altufyevskoe highway (Moscow), performed by the author in 2010–2016. 2. Materials and methods The basic stage of road condition evaluation is the determination of its technical and operational conditions or an integrated indicator of its performance (such integrated indicator (IIr) includes evaluating geometric parameters of the plan view, transverse profile, and longitudinal profile of the road, wearing course conditions and pavement strength, longitudinal and transverse evenness, adhesive properties of the wearing course, road shoulder conditions, dimensions of bridges and overpasses, traffic density and types of transport, as well as traffic safety). Partial design speed ratios at every typical road section are calculated to evaluate the influence of individual road parameters and characteristics on the integrated indicator of the road condition (IIr). At the present time, 10 partial design speed ratios are used. Four of those are directly related to the road pavement structure: DSR6 — partial design speed ratio considering the longitudinal evenness of the wearing course; DSR7 — partial design speed ratio considering the influence of the tire grip coefficient; DSR8 — partial design speed ratio considering the road pavement strength and conditions, calculated depending on the road pavement strength and wearing course conditions only in areas with visible cracks, rutting, subsidence and breaks; DSR9 — partial design speed ratio considering the evenness in the transverse direction, calculated depending on the rutting size (Ekbladand Lundström, 2018). 3. Influence of road parameters and characteristics on traffic comfort To ensure comfortable movement, traffic safety and the required speed, the wearing course shall be in good
Andrey Korochkin / Transportation Research Procedia 36 (2018) 315–319 Andrey Korochkin / Transportation Research Procedia 00 (2018) 000–000
317 3
condition. To meet that condition, the road structure shall be designed with consideration for the types of transport, assumed load, natural conditions in the region, etc. (Gokhman, 2015). In Russia, flexible pavements are mainly used. However, global trends and increasing axial loads encourage to apply other design solutions, e.g. rigid road pavements. Rigid pavements are already used on some roads, particularly, on motor highways. Frequently, the necessity for repair arises after the expiration of a particular period of cement-concrete wearing course operation (Deja, 2011). Therefore, in most cases, asphalt-concrete layers of various thickness are laid over the old cement-concrete wearing course for its capital repair or reconstruction. Besides, concurrently, rigid pavements with the asphalt-concrete wearing course are constructed. In Russia, due to a variety of reasons, an adverse situation related to the assurance of standard service life for road pavements has arisen. The actual period between repairs of federal roads amounts to 3–4 years (Ushakov, 2014), but lately it tends to decrease. Flexible pavements with the asphalt-concrete wearing course prevail on highways (97%), and only 3% of roads have the cement-concrete wearing course (Medres et al., 2017). Rutting, cracking and unevenness of asphalt-concrete wearing courses decrease traffic safety, vehicle speed and time between repairs, as well as increase fuel consumption. At present, upon design and construction of motor roads, the maximum design load amounts to 11.5 tons according to Regulations SP 4.13330 "Motor Roads" and State Standard GOST R 52748-2007 "Standard Loads, Loading Systems and Clearance Diagrams". However, the axial load of trucks manufactured and delivered to Russia amounts to approximately 14 tons (MAZ, Scania, MAN). Rigid structures with a specified durability allow for movement of such significant loads. 4. Rigid asphalt-concrete pavement as a means of increasing traffic safety Recently, rigid pavements have been increasingly applied in Russia due to the following long-term advantages: 1) load-bearing capacity of the road pavement structure becomes almost unlimited regardless of climatic effects. Concrete strength is 2–3.5 times higher than that of asphalt-concrete; 2) structure durability is significantly higher than that of flexible road pavements; 3) extended period between repairs; 3) absence of rutting; 4) increased tire grip coefficient for the cement-concrete wearing course. One of the important methods for extending the road pavement service life and traffic safety is the arrangement of the asphalt-concrete wearing course over the cement-concrete base course. Modern technologies of cement-concrete wearing course construction involve full automation of basic processes of laying and compacting concrete mixes, finishing concrete surfaces, arranging expansion joints and curing concrete. It allows for a significant increase in construction efficiency: improving wearing course evenness, increasing laying efficiency and wearing course service life, decreasing labor costs and intensity. Concrete slip-form pavers in one pass perform the entire set of works in the arrangement of high-strength wearing courses. If works are performed on the existing highways, the traditional method of cement-concrete wearing course repair is overlaying with asphalt-concrete layers of significant thickness. In accordance with the industrial road standards for the design of flexible road pavements, to limit the number of possible reflective cracks in the wearing course, the thickness of layers of materials containing an organic binder, laid over the road base of cement-bound materials, shall at least be equal to the thickness of cement-bound layers. The minimum thickness of layers shall comply with the requirements given in Table 2.3 (Guidelines on the design of rigid pavements, 2004). Thus, on highways with high traffic density, the thickness of asphalt-concrete layers on the cement-concrete base course shall amount to 18 cm. Recently, thin and ultra-thin wearing courses have become widely used internationally. They allow improving road performance and traffic safety. In France, several classes of thin asphalt-concrete wearing courses were developed. Those classes include thin layers of 35...50 mm in thickness and very thin layers of 30 mm in thickness. It is also allowed to use prefabricated thin mats that are subsequently glued to cement-concrete wearing courses. Those mats have greater cracking resistance but lower wear resistance.
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Andrey Korochkin / Transportation Research Procedia 36 (2018) 315–319 Andrey Korochkin / Transportation Research Procedia 00 (2018) 000–000
In the USA, ultra-thin NovaChip wearing course made of a hot asphalt-concrete mix has proved itself to be good. Three gradation types (A, B and C) with a maximum grain size of 4.75, 9.5 and 12.5 mm, respectively, are applied. This allows for the arrangement of layers with a thickness of 12.5, 16 and 19 mm, respectively. The binder content in a mix is within a range from 4.6 to 5.8%. In leading foreign countries, it has been established that the arrangement of a reliable structure with a high probability of failure-free operation, e.g. a rigid road pavement with the asphalt-concrete wearing course, increases traffic safety and speed, improves general road performance. 5. Results and discussion The wearing course quality directly affects such indicator of traffic flow movement as speed. When driving on a road with the unsatisfactory wearing course condition, the driver focuses on obstacles under the wheels rather than on the traffic situation. Such distraction may result in a road accident. Thus, the arrangement of accurately designed high-quality structures is required for the improvement of the traffic situation and safety as a whole. One of the solutions increasing wearing course durability is the arrangement of rigid pavements. However, in Russia, such solution is not popular due to more complex technology of the arrangement and high construction costs. According to the data of studies performed by the author, as well as those of the analysis of national and international best practices, rigid pavements have the following advantages that are pretty much ignored in Russia: significantly higher cement-concrete strength as compared to asphalt-concrete strength; stability of cement-concrete stress-related properties upon temperature change; cement-concrete strength increase over time under favorable operating conditions; availability of equipment for high-speed construction of concrete wearing courses with high evenness; high frost resistance of concrete upon application of superplasticizing admixtures and air entraining agents; in case of high construction quality and normal operating conditions, the wearing course service life before capital repair may reach 50 years; stability of the tire grip coefficient, its low dependency on the degree of wetting.
Those are the important criteria and factors that are vital for the improvement of traffic safety in Russia. 6. Conclusion The application (arrangement) of rigid pavements with the asphalt-concrete wearing course will significantly improve wearing course performance, increase traffic safety, convenience and comfort. References Dan, H.-C., He, L.-H., Xu, B., 2017. Experimental investigation on skid resistance of asphalt pavement under various slippery conditions. International Journal of Pavement Engineering, 6(18), 485–499. https://doi.org/10.1080/10298436.2015.1095901. Deja, J., 2011. Polish experiences in concrete roads construction. Alitinform5-6 (22), 53–67. Ekblad, J., Lundström, R., 2018. Causes of rutting in flexible and semi-rigid test sections after 14 years of service. International Journal of Pavement Engineering 4(19), 878–897. https://doi.org/10.1080/14680629.2017.1281151 Federal State Statistics Service, 2017. http://www.gks.ru (accessed9 December 2017). Gokhman, L., 2015. Increase in time between repairs. Avtomobilniye Dorogi 5(1002). Guidelines on the design of rigid pavements (in supersession of Industrial Construction Standards VSN 197-91), 2004. Ministry of Transport of the Russian Federation, Moscow. Klekovkina, M., Gorshkov, V., Lialinov, A., 2016. Development of methods for evaluating the impact of stress-strain state uniformity of composite pavements on road safety. Transportation Research Procedia 20, 301–304.https://doi.org/10.1016/j.trpro.2017.01.027. Konoplyanko, V., 1978. Traffic safety fundamentals. Publishing House of the Volunteer Society for Cooperation with the Army, Aviation, and Navy (DOSAAF), Moscow.
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Medres, C., Lazarev, Yu., Raty, Y., Bondarenko, A., 2017. Method of assessment and prediction of temperature conditions of roadway surfacing as a factor of the road safety. Transportation Research Procedia 20, 393–400.https://doi.org/10.1016/j.trpro.2017.01.064. Nosov, S., Kuzmichev, V., Repin, S., Maksimov, S., 2017. Methodology of ensuring road traffic safety with respect to road-building materials compaction efficiency factor. Transportation Research Procedia 20, 450–454. https://doi.org/10.1016/j.trpro.2017.01.073. State Traffic Safety Inspectorate, 2017. http://stat.gibdd.ru (accessed9 December 2017). Ushakov, V., 2014. Durable pavements for Russian highways. Eurasia Roads, 1, 23–25. Vasiliev, A. (ed.), 2004. Guide for road workers. Volume 2. Road repair and maintenance. Informavtodor, Moscow.
ScienceDirect ScienceDirect
Transportation Research Procedia 00 (2018) 000–000 Available online at www.sciencedirect.com Transportation Research Procedia 00 (2018) 000–000
ScienceDirect
www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia
Transportation Research Procedia 36 (2018) 315–319 www.elsevier.com/locate/procedia
Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018) Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018)
Impact of rigid pavements with the asphalt asphalt-concrete concrete wearing course Impact of rigidon pavements with the asphalt asphalt-concrete concrete road performance and traffic safetywearing course on road performance and traffic safety a
Andrey Korochkin Korochkin* Andrey Korochkin Korochkin*
Moscow Automobile and Road Construction State Technical University (MADI), 64 Leningradskiy Prosp., Moscow, 125319, Russia
a
Moscow Automobile and Road Construction State Technical University (MADI), 64 Leningradskiy Prosp., Moscow, 125319, Russia
Abstract Abstract The article presents basic parameters of road pavements, affecting perfor performance mance of motor roads and traffic safety. Current design loads on thepresents structure, peculiarities of of their influence on the wearingperfor course are given. Pavement repair technologies, influ influence ence of The article basic parameters road pavements, affecting performance mance of motor roads and traffic safety. Current design various coursepeculiarities defects on of thetheir accident rateon arethe described. Prospects and advantages rigidtechnologies, pavement with asphaltasphalt loads onwearing the structure, influence wearing course are given. Pavement of repair influ influence ence of concrete wearing course course defects are provided with regard rate to traffic safety improvement improvement. various wearing on the accident are described. Prospects and advantages of rigid pavement with asphaltasphalt concrete wearing course are provided with regard to traffic safety improvement improvement. ©2018 The Authors. Published by Elsevier B.V. © 2018 The Authors. Published by Elsevier B.V. ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) This is an accessPublished article under the CC BY-NC-ND ©2018 Theopen Authors. by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review review under responsibility theCC scientific committee of the Thirteenth International Conference on Organization and This is an open access article underof BY-NC-ND ND licenseof (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility ofthe the scientific committee the Thirteenth International Conference on Organization and Traffic Safety Management nagement in Large Cities (SPbOTSIC 2018) 2018). Peer-review review under responsibility of the scientific committee of Traffic Safety Management in Large Cities (SPbOTSIC 2018). the Thirteenth International Conference on Organization and nagement in Large Cities (SPbOTSIC 2018) 2018). Traffic Safety Management
Keywords:asphalt-concrete; cement-concrete; accident rate; traffic safety; strength; durability. Keywords:asphalt-concrete; cement-concrete; accident rate; traffic safety; strength; durability.
1. Introduction 1. Introduction As economy develops, transport flows on motor roads and highways increase. As a result, this leads to an increase in loads develops, on the pavement structure. Ever-increasing increasing represent increase. one of theAscauses of pavement As economy transport flows on motor roads loads and highways a result, this leadsdamage to an and deformation, deterioration of pavement performance performance. increase in loads on the pavement structure. Ever-increasing increasing loads represent one of the causes of pavement damage 2017 to the Russian Federal State Statistics Service data for 2017 (Federal State Statistics Service, 2017), performance. andAccording deformation, deterioration of pavement performance there are 1,408.8 thousand kilometers of motor roads in Russia, including 52 thousand kilometers of federal motor 2017 According to the Russian Federal State Statistics Service data for 2017 (Federal State Statistics Service, 2017), roads (Vasiliev, 2004). For comparison: the total length of motor roads in China amounts to 4,463.9 thousand . there are 1,408.8 thousand kilometers of motor roads in Russia, including 52 thousand kilometers of federal motor kilometers. ilometers. Resolution in the field of road construction only amounts extensiontoof4,463.9 the motor road roads (Vasiliev, 2004).. of Forissues comparison: the total length of motor implies roads innotChina thousand kilometers. ilometers. Resolution of issues in the field of road construction implies not only extension of the motor road * Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000 000-0000 . * E-mail:[email protected] Corresponding author. Tel.: +0-000-000-0000 ; fax: +0-000-000 000-0000 .
E-mail:[email protected] 2352-1465© 2018 The Authors. Published by Elsevier B.V. This is an open access under the CC by BY-NC-ND license (https://creativecommons.org/licenses/by https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under 2352-1465© 2018 Thearticle Authors. Published Elsevier B.V. responsibility the scientific committee the Thirteenth International Conference on Organization and Traffic Safety Management https://creativecommons.org/licenses/by-nc-nd/4.0/)Peer-review under in This is an openofaccess article under the CCof BY-NC-ND license (https://creativecommons.org/licenses/by Large Cities (SPbOTSIC 2018). responsibility of the scientific committee of the Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018).
2352-1465 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the Thirteenth International Conference on Organization and Traffic Safety Management in Large Cities (SPbOTSIC 2018). 10.1016/j.trpro.2018.12.091
316 2
Andrey Korochkin / Transportation Research Procedia 36 (2018) 315–319 Andrey Korochkin / Transportation Research Procedia 00 (2018) 000–000
network but maintenance of the existing network in good operating condition. Basic road performance indicators (Dan et al., 2017) are as follows: 1. speed ensured by road conditions 2. traffic convenience and safety 3. traffic capacity and level of congestion 4. allowable axial load 5. total mass of cars 6. ergonomic, aesthetic and environmental properties of the road Road pavement is one of the main factors affecting traffic safety. Therefore, its structure shall provide the required technical characteristics during the entire design service life. Non-observance of the requirements to road pavements leads to an increase in the number of accidents. The purpose of the study is to determine a dependence of traffic safety on the road pavement structure and wearing course condition, as well as to define a method of accident rate decrease by means of various engineering solutions. According to the State Traffic Safety Inspectorate (2017), 13–18% of road accidents related to adverse road conditions are caused by wearing course unevenness (Nosov et al., 2017). Road accidents occur due to a sudden speed change (emergency braking), a maneuver in plan view or their simultaneous performance. The probability of collision increases sharply in case of same-direction and opposite-direction traffic. Moreover, road unevenness causes suspension vibrations which may result in the loss of control. Vibrations in trailers and semi-trailers of road trains lead to an increase in the dynamic corridor, thus increasing the probability of collision and loosing lateral stability (Konoplyanko, 1978). Uneven roads increase drivers' fatigue, distract their attention from other road objects, decrease traffic capacity and, finally, decrease vehicle stock efficiency. In such cases, traffic management methods provide warnings for road users. Besides high-quality road construction, the only efficient method of wearing course evenness control is timely repair. However, it should be noted that repair works on trafficways of road and streets also create high-risk areas and significantly decrease transportation efficiency due to the formation of pre-congestion and congestion conditions (Klekovkina et al., 2016). The article is based on studies of M-2 "Crimea", M-9 "Baltic", A-107 MSRR (Moscow Small Ring Road) motor roads and Altufyevskoe highway (Moscow), performed by the author in 2010–2016. 2. Materials and methods The basic stage of road condition evaluation is the determination of its technical and operational conditions or an integrated indicator of its performance (such integrated indicator (IIr) includes evaluating geometric parameters of the plan view, transverse profile, and longitudinal profile of the road, wearing course conditions and pavement strength, longitudinal and transverse evenness, adhesive properties of the wearing course, road shoulder conditions, dimensions of bridges and overpasses, traffic density and types of transport, as well as traffic safety). Partial design speed ratios at every typical road section are calculated to evaluate the influence of individual road parameters and characteristics on the integrated indicator of the road condition (IIr). At the present time, 10 partial design speed ratios are used. Four of those are directly related to the road pavement structure: DSR6 — partial design speed ratio considering the longitudinal evenness of the wearing course; DSR7 — partial design speed ratio considering the influence of the tire grip coefficient; DSR8 — partial design speed ratio considering the road pavement strength and conditions, calculated depending on the road pavement strength and wearing course conditions only in areas with visible cracks, rutting, subsidence and breaks; DSR9 — partial design speed ratio considering the evenness in the transverse direction, calculated depending on the rutting size (Ekbladand Lundström, 2018). 3. Influence of road parameters and characteristics on traffic comfort To ensure comfortable movement, traffic safety and the required speed, the wearing course shall be in good
Andrey Korochkin / Transportation Research Procedia 36 (2018) 315–319 Andrey Korochkin / Transportation Research Procedia 00 (2018) 000–000
317 3
condition. To meet that condition, the road structure shall be designed with consideration for the types of transport, assumed load, natural conditions in the region, etc. (Gokhman, 2015). In Russia, flexible pavements are mainly used. However, global trends and increasing axial loads encourage to apply other design solutions, e.g. rigid road pavements. Rigid pavements are already used on some roads, particularly, on motor highways. Frequently, the necessity for repair arises after the expiration of a particular period of cement-concrete wearing course operation (Deja, 2011). Therefore, in most cases, asphalt-concrete layers of various thickness are laid over the old cement-concrete wearing course for its capital repair or reconstruction. Besides, concurrently, rigid pavements with the asphalt-concrete wearing course are constructed. In Russia, due to a variety of reasons, an adverse situation related to the assurance of standard service life for road pavements has arisen. The actual period between repairs of federal roads amounts to 3–4 years (Ushakov, 2014), but lately it tends to decrease. Flexible pavements with the asphalt-concrete wearing course prevail on highways (97%), and only 3% of roads have the cement-concrete wearing course (Medres et al., 2017). Rutting, cracking and unevenness of asphalt-concrete wearing courses decrease traffic safety, vehicle speed and time between repairs, as well as increase fuel consumption. At present, upon design and construction of motor roads, the maximum design load amounts to 11.5 tons according to Regulations SP 4.13330 "Motor Roads" and State Standard GOST R 52748-2007 "Standard Loads, Loading Systems and Clearance Diagrams". However, the axial load of trucks manufactured and delivered to Russia amounts to approximately 14 tons (MAZ, Scania, MAN). Rigid structures with a specified durability allow for movement of such significant loads. 4. Rigid asphalt-concrete pavement as a means of increasing traffic safety Recently, rigid pavements have been increasingly applied in Russia due to the following long-term advantages: 1) load-bearing capacity of the road pavement structure becomes almost unlimited regardless of climatic effects. Concrete strength is 2–3.5 times higher than that of asphalt-concrete; 2) structure durability is significantly higher than that of flexible road pavements; 3) extended period between repairs; 3) absence of rutting; 4) increased tire grip coefficient for the cement-concrete wearing course. One of the important methods for extending the road pavement service life and traffic safety is the arrangement of the asphalt-concrete wearing course over the cement-concrete base course. Modern technologies of cement-concrete wearing course construction involve full automation of basic processes of laying and compacting concrete mixes, finishing concrete surfaces, arranging expansion joints and curing concrete. It allows for a significant increase in construction efficiency: improving wearing course evenness, increasing laying efficiency and wearing course service life, decreasing labor costs and intensity. Concrete slip-form pavers in one pass perform the entire set of works in the arrangement of high-strength wearing courses. If works are performed on the existing highways, the traditional method of cement-concrete wearing course repair is overlaying with asphalt-concrete layers of significant thickness. In accordance with the industrial road standards for the design of flexible road pavements, to limit the number of possible reflective cracks in the wearing course, the thickness of layers of materials containing an organic binder, laid over the road base of cement-bound materials, shall at least be equal to the thickness of cement-bound layers. The minimum thickness of layers shall comply with the requirements given in Table 2.3 (Guidelines on the design of rigid pavements, 2004). Thus, on highways with high traffic density, the thickness of asphalt-concrete layers on the cement-concrete base course shall amount to 18 cm. Recently, thin and ultra-thin wearing courses have become widely used internationally. They allow improving road performance and traffic safety. In France, several classes of thin asphalt-concrete wearing courses were developed. Those classes include thin layers of 35...50 mm in thickness and very thin layers of 30 mm in thickness. It is also allowed to use prefabricated thin mats that are subsequently glued to cement-concrete wearing courses. Those mats have greater cracking resistance but lower wear resistance.
318 4
Andrey Korochkin / Transportation Research Procedia 36 (2018) 315–319 Andrey Korochkin / Transportation Research Procedia 00 (2018) 000–000
In the USA, ultra-thin NovaChip wearing course made of a hot asphalt-concrete mix has proved itself to be good. Three gradation types (A, B and C) with a maximum grain size of 4.75, 9.5 and 12.5 mm, respectively, are applied. This allows for the arrangement of layers with a thickness of 12.5, 16 and 19 mm, respectively. The binder content in a mix is within a range from 4.6 to 5.8%. In leading foreign countries, it has been established that the arrangement of a reliable structure with a high probability of failure-free operation, e.g. a rigid road pavement with the asphalt-concrete wearing course, increases traffic safety and speed, improves general road performance. 5. Results and discussion The wearing course quality directly affects such indicator of traffic flow movement as speed. When driving on a road with the unsatisfactory wearing course condition, the driver focuses on obstacles under the wheels rather than on the traffic situation. Such distraction may result in a road accident. Thus, the arrangement of accurately designed high-quality structures is required for the improvement of the traffic situation and safety as a whole. One of the solutions increasing wearing course durability is the arrangement of rigid pavements. However, in Russia, such solution is not popular due to more complex technology of the arrangement and high construction costs. According to the data of studies performed by the author, as well as those of the analysis of national and international best practices, rigid pavements have the following advantages that are pretty much ignored in Russia: significantly higher cement-concrete strength as compared to asphalt-concrete strength; stability of cement-concrete stress-related properties upon temperature change; cement-concrete strength increase over time under favorable operating conditions; availability of equipment for high-speed construction of concrete wearing courses with high evenness; high frost resistance of concrete upon application of superplasticizing admixtures and air entraining agents; in case of high construction quality and normal operating conditions, the wearing course service life before capital repair may reach 50 years; stability of the tire grip coefficient, its low dependency on the degree of wetting.
Those are the important criteria and factors that are vital for the improvement of traffic safety in Russia. 6. Conclusion The application (arrangement) of rigid pavements with the asphalt-concrete wearing course will significantly improve wearing course performance, increase traffic safety, convenience and comfort. References Dan, H.-C., He, L.-H., Xu, B., 2017. Experimental investigation on skid resistance of asphalt pavement under various slippery conditions. International Journal of Pavement Engineering, 6(18), 485–499. https://doi.org/10.1080/10298436.2015.1095901. Deja, J., 2011. Polish experiences in concrete roads construction. Alitinform5-6 (22), 53–67. Ekblad, J., Lundström, R., 2018. Causes of rutting in flexible and semi-rigid test sections after 14 years of service. International Journal of Pavement Engineering 4(19), 878–897. https://doi.org/10.1080/14680629.2017.1281151 Federal State Statistics Service, 2017. http://www.gks.ru (accessed9 December 2017). Gokhman, L., 2015. Increase in time between repairs. Avtomobilniye Dorogi 5(1002). Guidelines on the design of rigid pavements (in supersession of Industrial Construction Standards VSN 197-91), 2004. Ministry of Transport of the Russian Federation, Moscow. Klekovkina, M., Gorshkov, V., Lialinov, A., 2016. Development of methods for evaluating the impact of stress-strain state uniformity of composite pavements on road safety. Transportation Research Procedia 20, 301–304.https://doi.org/10.1016/j.trpro.2017.01.027. Konoplyanko, V., 1978. Traffic safety fundamentals. Publishing House of the Volunteer Society for Cooperation with the Army, Aviation, and Navy (DOSAAF), Moscow.
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