- Email: [email protected]
Accelerated Pavement Testing in Slovakia: APT Tester 105-03-01
Available online at www.sciencedirect.com
ScienceDirect Procedia Engineering 192 (2017) 765 – 770
TRANSCOM 2017: International scientific conference on sustainable, modern and safe transport
Accelerated Pavement Testing in Slovakia: APT Tester 105-03-01 Lubos Remeka*, Jan Mikolaja, Milan Skarupaa a
University of Žilina, Faculty of Civil Engineering, Univerzitná 8215/1, 010 26 Žilina, Slovakia
Abstract This article presents the APT (Accelerated Pavement Testing) facility constructed and operated by University of Zilina. The machine is designated as APT tester 105–03–01. The article describes tester’s technical properties, operational capabilities, sensory equipment embedded in the pavement and data gathering procedures. The device has several unique design solutions that make it stand out from similar facilities in the world: x The principle of fixed linear APT facility with loading unit not positioned in a fixed frame, but instead, moveable along a guiding rail to better simulate traffic loading. x Loading unit consisting of fixed and movable frame held by support connected by joints for better simulation of suspension like those found on truck axles. x The construction of the electric motor, gear box and frequency inverter and its mounting system on the loading unit. x Frequency converter controlled acceleration and deceleration and speed during the movement. x Hydraulic stabilization system stabilizing the movable frame preventing the load to tip the loading unit in the acceleration and deceleration stage. x Autonomous hydraulic system placed on the outer frame able to lift the loading unit and allows for free manipulation without acting on the pavement. 2017The The Authors. Published by Elsevier Ltd.is an open access article under the CC BY-NC-ND license ©©2017 Authors. Published by Elsevier Ltd. This Peer-review under responsibility of the scientific committee of TRANSCOM 2017: International scientific conference on (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review responsibility the scientific committee of TRANSCOM 2017: International scientific conference on sustainable, sustainable,under modern and safe of transport. modern and safe transport Keywords: Accelerated Pavement Testing; Pavement Performance; Pavement Management System
* Corresponding author. E-mail address: [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the scientific committee of TRANSCOM 2017: International scientific conference on sustainable, modern and safe transport
doi:10.1016/j.proeng.2017.06.132
766
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
1. The History of Accelerated Pavement Testing in Slovakia The history of Accelerated Pavement Testing in Slovakia started in 1984 by construction of the Circular Test Track (CTT) by the VUIS-CESTY, Ltd. research institute. The machine, shown in figure 1, was constructed to perform tests of pavements on a 1:1 scale. The machine elicited load with an actual vehicle axle weighing 115 kN (the EU standard for a permissible axle load). The basis of the CTT mechanical part consisted of three loading vehicles each of which has a driving axle. The vehicle was attached to the arms of a medium anchor clapper. The CTT’s electric part served to drive each vehicle by means of electro-motors and to control the entire CTT mechanical facility.
Fig 1. Circular Test Track 1984-2006.
The facility allowed a transversal shift of the loading vehicles of ± 950 mm. The vehicles moved on two doubled wheels equipped with 11,00R- 20 tires at a 0,7 MPa inflation pressure. The speed of the vehicle was limited to 60 km/hour, but the mean operational speed was 30 km/hour. The pavement testing track was 100 m long and 6 meter wide. The facility was used to test new pavement types, materials and other road equipment – rail crossing for instance in a 1:1 scale. The facility was in operation till 2006. [1] The most important outputs were pavement degradation curves used in Pavement Management System of Slovakia from 1996. As an example, in Figure 2, we present the trend line for degradation of longitudinal unevenness for specific pavement used in Slovakia’s pavement management system. In the chart, n is the number of Standard Axle Loads repetitions from the start of service to the expected date of pavement repair; N is the total number of Standard Axle Loads repetitions needed to achieve the load limit value. In this case, the parameter B 2,0 was derived for flexible pavements and parameter B 3,0 was derived for semi-rigid pavements. A warning value is at 60% difference between initial and limit value. Critical value is 40%.
Fig. 2. Degradation functions of longitudinal unevenness for flexible pavements B=2,0 and semi-rigid pavements B=3,0.
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
2. APT tester 105-03-01 Strategically focused, needs driven, pavement research programs have been shown to be most successful when carried out using a combination of laboratory, APT and LTPP (Long Term Pavement Performance Monitoring) data collection studies in conjunction with standard pavement management system monitoring procedures. At present LTPP is carried out on selected road sections of Slovakia’s road network using results of measurements carried out for the needs of Slovak Road Inventory. However, given the large number of input variables and conditions, and thus the large dispersion of the results, demand for a new experimental test facility arose. Design, construction and early operation of such facility were the objective of project “Independent research of Civil Engineering construction Elements Effectiveness” supported by the Research & Development Operational Programme funded by the European Regional Development Fund. 2.1. Design of APT tester 105-03-01 The facility was designed based on the requirements of researchers at the University of Zilina at the Department of Construction management. Design and construction was supplied by CEIT, a.s. (Central European Institute of Technology) The first designs were the usual fixed linear APT’s held by a frame construction. The subsequent design efforts were aimed to make the tester a semi-mobile linear APT facility, which could be fairly easily disassembled, transported and reassembled somewhere else. The frame was changed for a rail system leading the vehicle along its path. This however led to several design problems with suspension of the vehicle as well as material fatigue incurred by sharp accelerations and decelerations of the loading unit. These problems were solved by encasing the vehicle in outer frame and inner frame which could freely tilt, raise and sink within the outer frame. This arrangement is lead along a leading rail, moveable frame is suspended in the outer frame by suspension system similar to suspensions of axles in heavy trucks. The inner frame is also stabilized by hydraulic pistons which tighten in acceleration and deceleration providing support of the inner frame and loosen during constant movement enabling the vehicle to better copy pavement unevenness. The vehicle is powered by a 45 kW electric engine. The transition is a CLP HC VG 320, MOBIL SHC GEAR 320. Breaking is done by the electromotor itself, the power is recuperated and in form of heat lead to radiators. Main dimensions of the facility are shown in Tab 1, technical parameters are then listed in tab 2. Table 1. Main dimensions of APT tester 105-03-01 Dimensions Length
9 042 mm
Width
5 178 mm
Width with open doors
2 452 mm
Height
2 452 mm
Table 2. Technical parameters of APT tester 105-03-01 Technical Parameters Facility Construction Type
Accelerated Pavement Testing Facility Semi-mobile, Linear 105-03-01
Maximum velocity
2.2 m.s-1
Load
57.5 kN
Max acceleration
2 m.s-2
Max deceleration
5 m.s-2
Location
Indoor
767
768
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
Operational Temperature Operational Humidity Engine Power Transition Energy requirements
10 – 40 °C 30 - 80 % without condensation 45 kW CLP HC VG 320, MOBIL SHC GEAR 320 3+N+PE, AC, 50 Hz, 230/400, V, TN-S
The final design was the result of many person months spent by academic personnel and practitioners, in which financial limitations and high requirements on such tester resulted in probably the best value for money that could be achieved. Figure 3 shows the final design of APT tester 105-03-0, and its main constituents.
Fig. 3. Visualization of final design of the Tester 105-03-1. 1 Wheels, 2 Buffers, 3 Control panel, 4 Fuselage box, 5 Brake heat exchangers, 6 Supporting rail, 7 Guiding rail, 8 Load, 9 Rubber buffers, 10 Hydraulic liquid container, 11 Hydraulic system, 12 Motor for lifting of the loading unit, 13 Gear box for lifting of the loading unit, 14 Main electromotor, 15 Container for gear box oil, 16 Gear box, 17 Electromotor for lifting of the loading unit, 18 Loading unit
2.2. Pavement Design and Sensory Equipment The pavement test field has a length of 6 meters and a width of 2.2 meters. The pavement structure was designed as a pavement for a road with traffic load class Traffic load class III. It is a flexible pavement with bitumen concrete
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
surfacing. The wearing base layer is made of asphalt concrete AC 11 O; CA 35/50; 40 mm thick. The base course layer is made of asphalt concrete AC 16 P, CA 35/50; 80 mm thick. These layers are connected by penetrating coating PS; 0.5 kg/m2. The road base is a mechanically bound aggregate MSK 31.5 GB; 180 mm thick. Sub-base is gravel ŠD; 31.5 (45) GC; 200 mm thick. Conformity of all supplied materials has been confirmed by tests affirming the quality elaborate supplied by the constructor; quality of particular layers was confirmed through quality tests performed during the construction as prescribed in the test plan. Wearing base AC 11O; CA 35/50; 40 mm Base course AC 16 P, CA 35/50; 80 Mechanically bound aggregate 31.5 GB; 180
Gravel Sub-base SD; 31.5 (45) GC; 200 Elaston rubber Fig. 4. Pavement test field construction.
The earth work construction –subgrade, beneath the pavement is simulated with the Elaston rubber layer, the equivalent modulus of this layer lying on a concrete is extremely similar to an earthwork embankment. [2, 3] Sensor equipment for tensile tangential stress measurement composes 21 tenzometers with strain gauges based on the wӧhler bridge principle. These strain gauges had to withstand the embedding process – temperatures of up to 200 °C combined with high pressure and vibrations. The body of the tenzometer is hardened plastic, the sensitive parts are coated with teflon. The range of measurement is 3000 microstrain. The accuracy of measurement is a ratio of input voltage and existential voltage ≈ 1.3mVout/Vex. The strain gauge composes 2 tension gauges with resistance of 300400Ω. Additional 4 vertical strain tenzometers are embedded in the pavement at the bottom of the surfacing. Complementary set of sensors is embedded in the pavement for measurement of humidity and temperature within the pavement. At present, there is only limited capability to control the temperature of the pavement, however, the tester was built with the prospect to install infrared heater devices on the frame of the machine to simulate summer seasons. Two thermometers are embedded in the pavement capable of temperature measurement within -30 to +80°C interval with an accuracy of ± 0.5°C. Duo of humidity sensors are embedded in the subbase with the premise that an experiment involving waterlogging of the pavement should be required. Generally, many sources of information were used prior to the sensory equipment design. [4] The full sensor suite is shown on figure 5.
Fig. 5. Visualization of tenzometer placement in the pavement
The measured results are to be evaluated in conjunction with material research, namely rheological and deformational parameters of asphalt mixtures as well as fatigue of the asphalt construction. [5] 3. Data Collection and Readings Pavement performance data gathering during its whole life cycle is the main focus at this stage of the project. If the measured data are archived thoroughly, they may serve as a basis for the creation of important advisory models which are known as degradation or prediction models. We comprehend the deterioration of the pavement as gradual degradation of individual properties deteriorating under a variety of influences. The aging of the material and its fatigue characteristics have considerate impact on deterioration. For surfacing materials in particular, it is the transition from
769
770
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
a flexible to a plastic state continuing until reaching the limits of the infraction. Climatic conditions while important are disregarded at this stage of the research. [6] Three main characteristics are the subject of scrutiny: Unevenness, Macrotexture and Pavement strain measurement. Reading from sensor described in chapter 2.2 is shown in fig 6, in this case, the reading is from static loading, i.e. the loading was steadily increased through the wheel of the machine. Bottom of the surfacing course
[strain] 0.00016
0.00014
0.00012
0.0001
3000
3050
3100
3150
3200
3250
3300 t[s]
3050
3100
3150
3200
3250
3300 t[s]
[strain] -0.0002875 -0.00029 -0.0002925 -0.000295 -0.0002975 -0.0003 -0.0003025 3000
Vertical sensor on the bottom of the base course Fig. 6. Sensor reading: 0-6 ton load in 35 seconds.
At the start, the wheel was completely lifted of the pavement; the full weight of the axle (6 ton) was lowered in 35 seconds. The presented reading is from sensors directly under the axle. Strain can be easily recalculated to stress by applying of the Hook’s law. Acknowledgements This contribution is the result of the project implementation: "Independent Research of Civil Engineering Construction for Increase in Construction Elements Effectiveness" (ITMS: 26220220112) supported by the Research & Development Operational Programme funded by the ERDF. References [1] Fonód, A., 2005; Degradation of the bearing capacity of asphalt pavements, in Slovak Journal of Civil Engineering, ISSN: 1210-3896 (print version), ISSN: 1338-3973 (electronic version), pp. 35- 39. [2] Zgutova, K., Decky, M. and Ďurekova, D., 2012; Implementation of static theory of impulse into correlation relations of relevant deformation characteristics of earth construction. In SGEM 2012: 12th international multidisciplinary scientific geoconference, Albena, Bulgaria. ISSN 1314-2704, p. 107-115. [3] Pepucha, Ľ., Zgútová, K., Ďureková, D., Danišovič, P., Šrámek, J.: Determining of CBR values of pavement construction layers based on renewable material sources using non-destructive method. In: Advanced Materials Research Vol. 1001(2014), , ISSN 1662-8985 (web), ISSN 1022-6680 (print), 2014, s. 463-468. [4] Willis, J. R., 2008; “A synthesis of practical appropriate instrumentation use for accelerated pavement testing in the united states,” in Proc. International Conference on Accelerated Pavement Testing, Spain, Madrid 2008 [5] Schlosser, F., Šrameková, E. and Šrámek, J., 2014; Rheology, Deformational Properties and Fatigue of the Asphalt Mixtures. In: Advanced Materials Research Vols. 875-877(2014), ISSN 1662-8985 (web), ISSN 1022-6680 (print), p. 578-583. [6] Trojanová, M., Decký, M., Remišová, E.: The implication of climatic changes to asphalt pavement design. Volume 111, 2015, Pages 770-776. In: 24th Russian-Polish-Slovak Seminar on Theoretical Foundation of Civil Engineering, TFoCE 2015; ISSN: 18777058.
ScienceDirect Procedia Engineering 192 (2017) 765 – 770
TRANSCOM 2017: International scientific conference on sustainable, modern and safe transport
Accelerated Pavement Testing in Slovakia: APT Tester 105-03-01 Lubos Remeka*, Jan Mikolaja, Milan Skarupaa a
University of Žilina, Faculty of Civil Engineering, Univerzitná 8215/1, 010 26 Žilina, Slovakia
Abstract This article presents the APT (Accelerated Pavement Testing) facility constructed and operated by University of Zilina. The machine is designated as APT tester 105–03–01. The article describes tester’s technical properties, operational capabilities, sensory equipment embedded in the pavement and data gathering procedures. The device has several unique design solutions that make it stand out from similar facilities in the world: x The principle of fixed linear APT facility with loading unit not positioned in a fixed frame, but instead, moveable along a guiding rail to better simulate traffic loading. x Loading unit consisting of fixed and movable frame held by support connected by joints for better simulation of suspension like those found on truck axles. x The construction of the electric motor, gear box and frequency inverter and its mounting system on the loading unit. x Frequency converter controlled acceleration and deceleration and speed during the movement. x Hydraulic stabilization system stabilizing the movable frame preventing the load to tip the loading unit in the acceleration and deceleration stage. x Autonomous hydraulic system placed on the outer frame able to lift the loading unit and allows for free manipulation without acting on the pavement. 2017The The Authors. Published by Elsevier Ltd.is an open access article under the CC BY-NC-ND license ©©2017 Authors. Published by Elsevier Ltd. This Peer-review under responsibility of the scientific committee of TRANSCOM 2017: International scientific conference on (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review responsibility the scientific committee of TRANSCOM 2017: International scientific conference on sustainable, sustainable,under modern and safe of transport. modern and safe transport Keywords: Accelerated Pavement Testing; Pavement Performance; Pavement Management System
* Corresponding author. E-mail address: [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the scientific committee of TRANSCOM 2017: International scientific conference on sustainable, modern and safe transport
doi:10.1016/j.proeng.2017.06.132
766
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
1. The History of Accelerated Pavement Testing in Slovakia The history of Accelerated Pavement Testing in Slovakia started in 1984 by construction of the Circular Test Track (CTT) by the VUIS-CESTY, Ltd. research institute. The machine, shown in figure 1, was constructed to perform tests of pavements on a 1:1 scale. The machine elicited load with an actual vehicle axle weighing 115 kN (the EU standard for a permissible axle load). The basis of the CTT mechanical part consisted of three loading vehicles each of which has a driving axle. The vehicle was attached to the arms of a medium anchor clapper. The CTT’s electric part served to drive each vehicle by means of electro-motors and to control the entire CTT mechanical facility.
Fig 1. Circular Test Track 1984-2006.
The facility allowed a transversal shift of the loading vehicles of ± 950 mm. The vehicles moved on two doubled wheels equipped with 11,00R- 20 tires at a 0,7 MPa inflation pressure. The speed of the vehicle was limited to 60 km/hour, but the mean operational speed was 30 km/hour. The pavement testing track was 100 m long and 6 meter wide. The facility was used to test new pavement types, materials and other road equipment – rail crossing for instance in a 1:1 scale. The facility was in operation till 2006. [1] The most important outputs were pavement degradation curves used in Pavement Management System of Slovakia from 1996. As an example, in Figure 2, we present the trend line for degradation of longitudinal unevenness for specific pavement used in Slovakia’s pavement management system. In the chart, n is the number of Standard Axle Loads repetitions from the start of service to the expected date of pavement repair; N is the total number of Standard Axle Loads repetitions needed to achieve the load limit value. In this case, the parameter B 2,0 was derived for flexible pavements and parameter B 3,0 was derived for semi-rigid pavements. A warning value is at 60% difference between initial and limit value. Critical value is 40%.
Fig. 2. Degradation functions of longitudinal unevenness for flexible pavements B=2,0 and semi-rigid pavements B=3,0.
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
2. APT tester 105-03-01 Strategically focused, needs driven, pavement research programs have been shown to be most successful when carried out using a combination of laboratory, APT and LTPP (Long Term Pavement Performance Monitoring) data collection studies in conjunction with standard pavement management system monitoring procedures. At present LTPP is carried out on selected road sections of Slovakia’s road network using results of measurements carried out for the needs of Slovak Road Inventory. However, given the large number of input variables and conditions, and thus the large dispersion of the results, demand for a new experimental test facility arose. Design, construction and early operation of such facility were the objective of project “Independent research of Civil Engineering construction Elements Effectiveness” supported by the Research & Development Operational Programme funded by the European Regional Development Fund. 2.1. Design of APT tester 105-03-01 The facility was designed based on the requirements of researchers at the University of Zilina at the Department of Construction management. Design and construction was supplied by CEIT, a.s. (Central European Institute of Technology) The first designs were the usual fixed linear APT’s held by a frame construction. The subsequent design efforts were aimed to make the tester a semi-mobile linear APT facility, which could be fairly easily disassembled, transported and reassembled somewhere else. The frame was changed for a rail system leading the vehicle along its path. This however led to several design problems with suspension of the vehicle as well as material fatigue incurred by sharp accelerations and decelerations of the loading unit. These problems were solved by encasing the vehicle in outer frame and inner frame which could freely tilt, raise and sink within the outer frame. This arrangement is lead along a leading rail, moveable frame is suspended in the outer frame by suspension system similar to suspensions of axles in heavy trucks. The inner frame is also stabilized by hydraulic pistons which tighten in acceleration and deceleration providing support of the inner frame and loosen during constant movement enabling the vehicle to better copy pavement unevenness. The vehicle is powered by a 45 kW electric engine. The transition is a CLP HC VG 320, MOBIL SHC GEAR 320. Breaking is done by the electromotor itself, the power is recuperated and in form of heat lead to radiators. Main dimensions of the facility are shown in Tab 1, technical parameters are then listed in tab 2. Table 1. Main dimensions of APT tester 105-03-01 Dimensions Length
9 042 mm
Width
5 178 mm
Width with open doors
2 452 mm
Height
2 452 mm
Table 2. Technical parameters of APT tester 105-03-01 Technical Parameters Facility Construction Type
Accelerated Pavement Testing Facility Semi-mobile, Linear 105-03-01
Maximum velocity
2.2 m.s-1
Load
57.5 kN
Max acceleration
2 m.s-2
Max deceleration
5 m.s-2
Location
Indoor
767
768
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
Operational Temperature Operational Humidity Engine Power Transition Energy requirements
10 – 40 °C 30 - 80 % without condensation 45 kW CLP HC VG 320, MOBIL SHC GEAR 320 3+N+PE, AC, 50 Hz, 230/400, V, TN-S
The final design was the result of many person months spent by academic personnel and practitioners, in which financial limitations and high requirements on such tester resulted in probably the best value for money that could be achieved. Figure 3 shows the final design of APT tester 105-03-0, and its main constituents.
Fig. 3. Visualization of final design of the Tester 105-03-1. 1 Wheels, 2 Buffers, 3 Control panel, 4 Fuselage box, 5 Brake heat exchangers, 6 Supporting rail, 7 Guiding rail, 8 Load, 9 Rubber buffers, 10 Hydraulic liquid container, 11 Hydraulic system, 12 Motor for lifting of the loading unit, 13 Gear box for lifting of the loading unit, 14 Main electromotor, 15 Container for gear box oil, 16 Gear box, 17 Electromotor for lifting of the loading unit, 18 Loading unit
2.2. Pavement Design and Sensory Equipment The pavement test field has a length of 6 meters and a width of 2.2 meters. The pavement structure was designed as a pavement for a road with traffic load class Traffic load class III. It is a flexible pavement with bitumen concrete
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
surfacing. The wearing base layer is made of asphalt concrete AC 11 O; CA 35/50; 40 mm thick. The base course layer is made of asphalt concrete AC 16 P, CA 35/50; 80 mm thick. These layers are connected by penetrating coating PS; 0.5 kg/m2. The road base is a mechanically bound aggregate MSK 31.5 GB; 180 mm thick. Sub-base is gravel ŠD; 31.5 (45) GC; 200 mm thick. Conformity of all supplied materials has been confirmed by tests affirming the quality elaborate supplied by the constructor; quality of particular layers was confirmed through quality tests performed during the construction as prescribed in the test plan. Wearing base AC 11O; CA 35/50; 40 mm Base course AC 16 P, CA 35/50; 80 Mechanically bound aggregate 31.5 GB; 180
Gravel Sub-base SD; 31.5 (45) GC; 200 Elaston rubber Fig. 4. Pavement test field construction.
The earth work construction –subgrade, beneath the pavement is simulated with the Elaston rubber layer, the equivalent modulus of this layer lying on a concrete is extremely similar to an earthwork embankment. [2, 3] Sensor equipment for tensile tangential stress measurement composes 21 tenzometers with strain gauges based on the wӧhler bridge principle. These strain gauges had to withstand the embedding process – temperatures of up to 200 °C combined with high pressure and vibrations. The body of the tenzometer is hardened plastic, the sensitive parts are coated with teflon. The range of measurement is 3000 microstrain. The accuracy of measurement is a ratio of input voltage and existential voltage ≈ 1.3mVout/Vex. The strain gauge composes 2 tension gauges with resistance of 300400Ω. Additional 4 vertical strain tenzometers are embedded in the pavement at the bottom of the surfacing. Complementary set of sensors is embedded in the pavement for measurement of humidity and temperature within the pavement. At present, there is only limited capability to control the temperature of the pavement, however, the tester was built with the prospect to install infrared heater devices on the frame of the machine to simulate summer seasons. Two thermometers are embedded in the pavement capable of temperature measurement within -30 to +80°C interval with an accuracy of ± 0.5°C. Duo of humidity sensors are embedded in the subbase with the premise that an experiment involving waterlogging of the pavement should be required. Generally, many sources of information were used prior to the sensory equipment design. [4] The full sensor suite is shown on figure 5.
Fig. 5. Visualization of tenzometer placement in the pavement
The measured results are to be evaluated in conjunction with material research, namely rheological and deformational parameters of asphalt mixtures as well as fatigue of the asphalt construction. [5] 3. Data Collection and Readings Pavement performance data gathering during its whole life cycle is the main focus at this stage of the project. If the measured data are archived thoroughly, they may serve as a basis for the creation of important advisory models which are known as degradation or prediction models. We comprehend the deterioration of the pavement as gradual degradation of individual properties deteriorating under a variety of influences. The aging of the material and its fatigue characteristics have considerate impact on deterioration. For surfacing materials in particular, it is the transition from
769
770
Lubos Remek et al. / Procedia Engineering 192 (2017) 765 – 770
a flexible to a plastic state continuing until reaching the limits of the infraction. Climatic conditions while important are disregarded at this stage of the research. [6] Three main characteristics are the subject of scrutiny: Unevenness, Macrotexture and Pavement strain measurement. Reading from sensor described in chapter 2.2 is shown in fig 6, in this case, the reading is from static loading, i.e. the loading was steadily increased through the wheel of the machine. Bottom of the surfacing course
[strain] 0.00016
0.00014
0.00012
0.0001
3000
3050
3100
3150
3200
3250
3300 t[s]
3050
3100
3150
3200
3250
3300 t[s]
[strain] -0.0002875 -0.00029 -0.0002925 -0.000295 -0.0002975 -0.0003 -0.0003025 3000
Vertical sensor on the bottom of the base course Fig. 6. Sensor reading: 0-6 ton load in 35 seconds.
At the start, the wheel was completely lifted of the pavement; the full weight of the axle (6 ton) was lowered in 35 seconds. The presented reading is from sensors directly under the axle. Strain can be easily recalculated to stress by applying of the Hook’s law. Acknowledgements This contribution is the result of the project implementation: "Independent Research of Civil Engineering Construction for Increase in Construction Elements Effectiveness" (ITMS: 26220220112) supported by the Research & Development Operational Programme funded by the ERDF. References [1] Fonód, A., 2005; Degradation of the bearing capacity of asphalt pavements, in Slovak Journal of Civil Engineering, ISSN: 1210-3896 (print version), ISSN: 1338-3973 (electronic version), pp. 35- 39. [2] Zgutova, K., Decky, M. and Ďurekova, D., 2012; Implementation of static theory of impulse into correlation relations of relevant deformation characteristics of earth construction. In SGEM 2012: 12th international multidisciplinary scientific geoconference, Albena, Bulgaria. ISSN 1314-2704, p. 107-115. [3] Pepucha, Ľ., Zgútová, K., Ďureková, D., Danišovič, P., Šrámek, J.: Determining of CBR values of pavement construction layers based on renewable material sources using non-destructive method. In: Advanced Materials Research Vol. 1001(2014), , ISSN 1662-8985 (web), ISSN 1022-6680 (print), 2014, s. 463-468. [4] Willis, J. R., 2008; “A synthesis of practical appropriate instrumentation use for accelerated pavement testing in the united states,” in Proc. International Conference on Accelerated Pavement Testing, Spain, Madrid 2008 [5] Schlosser, F., Šrameková, E. and Šrámek, J., 2014; Rheology, Deformational Properties and Fatigue of the Asphalt Mixtures. In: Advanced Materials Research Vols. 875-877(2014), ISSN 1662-8985 (web), ISSN 1022-6680 (print), p. 578-583. [6] Trojanová, M., Decký, M., Remišová, E.: The implication of climatic changes to asphalt pavement design. Volume 111, 2015, Pages 770-776. In: 24th Russian-Polish-Slovak Seminar on Theoretical Foundation of Civil Engineering, TFoCE 2015; ISSN: 18777058.