TEST ROAD THE ROAD OF EXPERIMENTAL PAVEMENT STRUCTURES

Transcription

1 TEST ROAD THE ROAD OF EXPERIMENTAL PAVEMENT STRUCTURES

2 TABLE OF CONTENTS 3 Idea of the project Construction phase Pavement structures 15 Research methodology and equipment Measurement of traffic flow Measurement of temperature and moisture in different layers of pavement structure 15 Research results Traffic flow and ESALs Results of temperature and moisture distribution in pavement structure Results of visual assessment of pavement distress Results of road surface condition Results of bearing capacity Modeling with HDM Measurement of rutting, pavement roughness, pavement transverse and longitudinal gradients and texture Visual assessment of pavement distress Measurement of pavement equivalent modulus with Falling Weight Deflectometer (FWD) Measurement of pavement deflection with Benkelman Beam Measurement of skid resistance of asphalt wearing layers with pendulum device 3 Findings after 7 years of exploitation

3 IDEA OF THE PROJECT Road pavement structures are subjected to wide range of traffic loads and environmental impacts that are applied hourly, daily, and weekly. The most common problems during asphalt pavement structure exploitation are the formation of ruts, fatigue, as well as thermal cracking, deterioration, aging and water susceptibility. Over the years, a significant amount of effort has been spent on developing methods to objectively evaluate the condition of pavements. The scientists made an attempt to determine the performance of road pavement structures by constructing and testing them in special test polygons. LITHUANIA Change of road condition, longterm monitoring of actual loads and climatic conditions enables to determine degradation mechanisms, select stable building materials and their mixtures, rational use of asphalt paving technologies and to improve quality control. Seeking to determine the suitable and costeffective road asphalt pavement structures with a longer service life, Lithuanian Road Administration under the Ministry of Transport and Communications decided to install the Test Road and together with group of researchers from Vilnius Gediminas Technical University Road Department and Road Research Institute have chosen the suitable location for it. The Test Road have been contributed by JSC Fegda in Starting from autumn of that year monitoring and research are performed by Road Reserch Institute and Department of Roads from Vilnius Gediminas Technical University with assistance of Public Company Road and Transport Research Institute. PAGIRIAI Kalno g. CAPITAL Vilnius Pagiriai Location of the test road

4 CONSTRUCTION PHASE The location in Pagiriai (about 20 km from the capital of Lithuania Vilnius) was selected for constructing the Test Road section. This location fulfil all the conditions required for experiment: it has a sufficient heavy traffic volume, is located in an open terrain, has no horizontal plan curves or vertical curves in longitudinal section and could be distinguished by the same irrigation conditions within the whole route of the road section.,,automobile roads corresponds to the III category (2 traffic lanes, pavement width 7 m, roadside width 1m) and the III class of pavement structure class (ESALs of kn = ( ) mln). The Test Road, which is in total 710 m long, consists of 23 sectors of 30 m long and one 20 m long sectors. Three sectors additionally are divided into 15 m sections. The pavement structures of various types were constructed at these sectors. During subgrade installation in July August 2007 the uniform subgrade strength was achieved removing the previously installed layer in the pavement and subgrade, which was formed from a variety of construction waste, and its heterogeneous soil. Frost blanket and base layers were installed in August September. The strength of subgrade, frost blanket and base layers were tested using plate static loading test and falling weight deflectometer. Asphalt layers (base, binder and wearing layers) were installed in September October The parameters of experimental pavement structures road s transverse profile according to Technical Construction Regulations The Test Road

5 During pavement structures construction period two types of transducers in different layers were installed. Stress transducers ( SOPT Soil pressure transducers ) were installed at the surface of subgrade (structures No 19 and No 25) and surface of frost blanket layer (structures No 19, No 24 and No 25) and surface of base layer (structures No 19, No 20, No 21, No 22 and No 23). Strain transducers ( PAST Pavement strain transducers ) were installed at the bottom of each asphalt layer in every structure. Horizontal marking on the road surface was accomplished in October and all the installation works of the road were finished in 17th of October. The road leads to gravel quarries where one traffic line is used by loaded traffic and another by unloaded. PAVEMENT STRUCTURES Various materials were used for every layer of the Test Road (Table 1). The frost blanket layer was built from sand (0/4, 0/11); the base layer from crushed dolomite and granite (0/56, 0/32), the mix of 50% crushed granite and 50% sand and gravel, crushed gravel mix, gravel and sand mix and the reclaimed asphalt. The asphalt base layer was built from AC32PS crushed dolomite, gravel, % crushed gravel, 50% crushed dolomite and 50% crushed gravel; asphalt binder layer: AC16AS, AC16AS PMB crushed granite 11/16 + crushed dolomite 5/8 + (crushed dolomite and crushed granite 8/11, 50% and 50%); crushed granite 8/11 and 11/16 + crushed gravel (rest of aggregates); crushed dolomite 8/11 and 11/16 + crushed gravel (rest of aggregates); 50% crushed granite + 50% sand; % crushed granite; % crushed gravel. Asphalt wearing layer: 0/11 AC11VS, SMA11S, SMA11S PMB, Confalt. The thickness for every pavement structure were chosen according to reference pavement structure, which was made from 4 cm asphalt wearing layer AC11VS; 4 cm asphalt binder layer AC16AS; 10 cm asphalt base layer AC32PS; 20 cm base layer crushed dolomite 0/56; 47 cm frost blanket layer sand 0/11 (No 19). No of pavement structure Asphalt wearing layer (thickness, AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 9 Confalt (4 Asphalt binder layer (thickness, AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 Asphalt base layer (thickness, AC 32 PS (14 Base layer (thickness, 0/32 Gravelsand mix (20 0/56 Crushed dolomite (15 0/32 Gravelsand mix (20 0/56 Crushed dolomite (30 0/56 Crushed dolomite (20 Aggregate milled asphalt concrete (10 rushed dolomite (10 0/32 Gravelsand mix (20 Frost blanket layer (thickness, 0/11 Sand (43 0/11 Sand (32 0/4 Sand (37 0/4 Sand (47 rushed granite and sand mix (20 8 0/56 Crushed granite (20 0/56 Crushed dolomite (20

6 /11 SM SMA 11 S (4 0/11 SM(PMB 11 ) SMA 11 S (4 0/11 SM (PMB) SMA 11 S (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 9 AC 11VS (4 9 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 11VS (4 AC 16 AS (4 PMB AC 16 AS (4 AC 16 AS (4 1 AC 16 AS (4 2 AC 16 AS (4 3 AC 16 AS (4 4 AC 16 AS (4 5 AC 16 AS (4 6 AC 16 AS (4 AC 16 AS (4 9 AC 16 AS (4 9 AC 16 AS (4 9 AC 16 AS (4 9 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS (4 AC 16 AS ( /56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite ( /56 Crushed dolomite ( /56 Crushed dolomite (20 0/56 Crushed dolomite (20 0/56 Crushed dolomite ( /56 Crushed dolomite ( /56 Crushed dolomite (20 0/56 Crushed dolomite ( crushed granite 11/16 + crushed dolomite 5/8 + (crushed dolomite and crushed granite 8/11, 50% and 50%); 2. crushed granite 8/11 and 11/16 + crushed gravel (rest of aggregates); 3. crushed dolomite 8/11 and 11/16 + crushed gravel (rest of aggregates); 4. 50% crushed granite + 50% sand; 5. % crushed granite; 6. % crushed gravel; 7. 50% crushed dolomite + 50% crushed gravel; 8. 50% crushed granite + 50% sand and gravel mix; 9. geosynthetics between asphalt wearing layer and asphalt binder layer, asphalt binder layer and asphalt base layer; 10. geosynthetics between base layer and frost blanket layer; 11. PMB (polymer modified bitumen). REFERENCE PAVEMENT STRUCTURE Pavement structures in Test Road

7 RESEARCH METHODOLOGY AND EQUIPMENT Every year at the Test Road sections these measurements are made: measurement of traffic flow, measurement of temperature and moisture in different layers of pavement structure, measurement of rutting, measurement of pavement roughness, measurement of pavement transverse and longitudinal gradients, visual assessment of pavement distress, measurement of pavement equivalent modulus with Falling Weight Deflectometer (FWD), measurement of pavement deflection with Benkelman Beam, measurement of skid resistance in asphalt wearing layer with pendulum device. Measurement of traffic flow Pavement structures in Test Road The traffic flow is measuring consistently after the first car passed after opening of the road. For the classification of traffic flow the induction loops, installed into road pavement, were used as well as the Loop profiler classificatory. All vehicle are classified in to 10 class (from motorcycles, light cars to busses) and were normed under ESALs= kn. According to the data from classifier Loop Profiler, it was noticed that daily heavy vehicles is about 17% of all traffic. The transport intensity and flow monitoring tests showed that 2 axle trucks in the test section is about 15.5% of heavy vehicles, 3 axle is about 66.9% and 2 axle trucks with 3 axle trailers is about 11.1%. The pictures below show the types of heavy vehicles that were registered during the visual traffic flow monitoring tests.

8 0,3 % 0,7 % 11,1 % 5,4 % 15,5 % 66,9 % Asphalt Pavement, 7 m 2 m 2 m 2 m Measurement of temperature and moisture in different layers of pavement structure Monitoring of pavement structure strength changes raise the need of temperature and moisture sensors installation. The moisture and temperature sensors 2 m 0,75 0,75 2 m are installed in four pavement structure sectors in different levels of pavement Content of heavy vehicles 2 axle 3 axle 4 axle or 2 axle with 2 axle trailer Installation of inductive loops for traffic flow measurements structure. The data of temperature and moisture is registering consistently since installation of each sensor station. 3 axle with 3axle trailer 2 axle with 3 axle trailer or 3 axle with 2 axle trailer bus Temperature sensors probe PT Installation of temperature and moisture sensors Moisture sensors probe PICOT3P type Pavement structure No Depth of temperature sensor, cm Depth of moisture sensor, cm surface The installation levels of temperature and moisture sensors in pavement structure sectors

9 Measurement of rutting, pavement roughness, pavement transverse and longitudinal gradients and texture Research of road surface conditions (roughness of surface (IRI), ruts, transverse and longitudinal gradients of pavement surface, texture of pavement surface) were performed using a mobile laboratory RST28. The measurements of rut depth, transverse and longitudinal gradients of pavement surface are made every 1 m, 30 values in total for each pavement structure. The average depth of the right rut, the left rut and the maximum clearance was counted at every pavement structure and the average of transverse and longitudinal gradients was counted in each structure section. Measurement of road condition Using the very latest laser scanning technology coupled with a high precision navigation system, IGI mbh and 3D Laser Mapping have joined forces to offer a novel 3D mapping system to scan roads, buildings etc. from a moving vehicle. Visual assessment of pavement distress Pavement distresses by visual assessment method were defined by Methodology for asphalt pavements defects detection. This methodology used mostly for cracking evaluation (longitudinal, thermal and structural). Visual measurements are made in each spring and autumn. Measurement of pavement equivalent modulus with Falling Weight Deflectometer (FWD) The bearing capacity of pavement structures are evaluating by nondestructive method Falling Weight Deflectometer (FWD). Measuring with FWD the pavement structure deflection from dynamic loading is registering. Measurements are taking in 4 points of each section in the rut of the right wheel and between the ruts. Measurement of pavement deflection with Benkelman Beam Measurements of the bearing capacity using the Benkelman beam were performed in 4 points of each section in the rut and between the ruts of both traffic lanes (the loaded and unloaded). The Benkalman beam is nondescrutive portable testdevice, which is able to record the pavement surface deflections occuring under actual truck traffic loading. These deflections are generally generated using with a loaded truck typically kn on a single axle with dual tires, tire pressure, dimension etc. Measurement is made by placing the tip of the beam between the dual tires and measuring the pavement surface rebound as the truck is moved away.

10 Measurement of skid resistance of asphalt wearing layers with pendulum device Pendulum device gives a measure of the friction between a skidding tyre and wet road surface. It provides a practical means of obtaining reliable evidence on which to take the appropriate measures to increase skid resistance. The test is performed according standard EN 364 Road and airfield surface characteristics Test methods Part 4: Method for measurement of slip/skid resistance of a surface: The pendulum test. Measurements were taken on loaded and unloaded traffic lines in each section every spring and autumn. RESEARCH RESULTS Traffic flow and ESALs During 7.5 years 3.4 mln cars passed on the Test Road in that number 0.6 mln were heavy traffic. The highest traffic intensity in April October on this road depends on construction work around the Vilnius city and region that needs materials from the quarries. The average daily traffic flow of Test Road is more than vehicles per day. Average annual loading of ESALs in average are applied. Total amount of ESALs since the beginning of road exploitation until March 2015 was Traffic flow, units Heavy vehicles (over 3,5 t) volume Light vehicles (up to 3,5 t) volume 90.0 Percentage composition of heavy vehicles in general traffic volume Percentage composition, % Year 0.0 Distribution of yearly traffic intensity Average daily vehicle traffic, units Year Total vehicles Heavy vehicles Average annual daily traffic intensity

11 ESALs ESALs of the one year ESALs from the beginning of Test Road exploitation The average temperature, C The surface of asphalt 2 cm depth 4 cm depth 8 cm depth 10 cm depth Year Date Daily values of average temperatures of asphalt layers in 2014 in structure No The surface of asphalt 2 cm depth 4 cm depth 8 cm depth 10 cm depth Distribution of ESALs Results of temperature and moisture distribution in pavement structure The average temperature, C Daily values of average temperatures and moisture in different layers of four pavement structures (No 4; No 12; No 18; No 24;) are monitoring. Monitoring of pavement structure No 18 is started from 2009 and of pavement structures No 4, No 12 and No 24 from July The temperature amplitude of asphalt pavement surface vary from 66 to 69 C. Temperature transitions from positive to negative and vice versa in asphalt pavement surface in (from October to April) were registered from 120 to times, and in 4 cm depth from 88 to 94 times. Daily temperature transitions through the 0 point were from 1 to 5 times. Frost heave at the depth of cm takes about 2 months, at the depth of cm about 6 weeks, at the depth of cm up to 4 weeks. Variation of moisture depends on frost depth. The average temperature, C The surface of asphalt 2 cm depth 4 cm depth 8 cm depth 10 cm depth Date Daily values of average temperatures of asphalt layers in structure No Date Daily values of average temperatures and moistures of subgrade in structure No 18 Results of visual assessment of pavement distress Every year the cracks propagations of violation. The change of climate had no influence of their formation. pavement structures were measured on a Test Road section. Measurements of pavement structure cracking were carried out in spring and autumn. During 5 years of the Test Road exploitation, only longitudinal and transverse cracks were identified. Longitudinal cracks are running parallel to the pavement center lane, while transverse cracks extend across the center lane. The mostly transvers cracking appears in pavement structure with semi rigid wearing layer. Results of visual assessment revealed that longitudinal and transverse cracks emerged by construction technology

12 Longitudinal cracking emerged by construction technology violation Results of road surface condition Daily values of average temperatures and moisture in different layers of four pavement structures (No 4; No 12; No 18; No 24;) are monitoring. Monitoring of pavement structure No 18 is started from 2009 and of pavement structures No 4, No 12 and No 24 from July The temperature amplitude of asphalt pavement surface vary from 66 to 69 C. Temperature transitions from positive to negative and vice versa in asphalt pavement surface in (from October to April) were registered from 120 to times, and in 4 cm depth from 88 to 94 times. Daily temperature transitions through the 0 point were from 1 to 5 times. Frost heave at the depth of cm takes about 2 months, at the depth of cm about 6 weeks, at the depth of cm up to 4 weeks. Variation of moisture depends on frost depth ESAL ( ) ESAL ( ) ESAL ( ) ESAL ( ) ESAL ( ) ESAL ( ) ESAL ( ) 2.5 IRI, m/km Stucture No ESAL ( ) ESAL ( ) IRI, m/km Stucture No

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