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Road Maintenance with Geosynthetics. K.Boychev. Crack Appearance on Bituminous Roads - Reflective Cracking - Thermal Cracking - Differential Settlements - Frost Heave (- Rutting). Crack Appearance on Bituminous Roads (e.g. Differential Settlements).
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Road Maintenance with Geosynthetics K.Boychev
Crack Appearance on Bituminous Roads- Reflective Cracking- Thermal Cracking- Differential Settlements- Frost Heave(- Rutting)
Crack Appearance on Bituminous Roads(e.g. Differential Settlements)
Crack Appearance on Bituminous Roads(e.g. Differential Settlements)
Paving Product Matrix Paving Products SAMI / reflective cracking “Stress Absorbing Membrane Interlayer” Asphalt reinforcement Non-woven Continuous filament Geocomposites Geogrids Non-woven Staple/short fiber Glass PET Coated/ Uncoated PP/PET nonwoven + Glass Uncoated PP or PET
PGM is a mechanically bonded continuous filament nonwoven of 100% Polypropylene with optimum bitumen retention capacity. (EN 15381 or acc. Texas D.O.T Item 3099) PGM • Reflective Cracking (STR) + Seals the surface (B) Literature: EN 15381 PGM-G is a high strength geocomposite, PGM + alkali resistant glass fibre reinforcement Group 2 PGM-G30/30 E PGM-G50/50 E PGM-G100/100 E Group 1 PGM-G50/50 PGM-G100/100 PGM-G150/150 • Reflective Cracking(STR)+Seals the surface(B)+Reinforcement(R) Literature: EN 15381
Road Construction – General Location of PGM, PGM-G & PGM-G E Literature GESTRATA Handbook Sep.2002
Road Construction – Stress Relieving Layer Conventional Method Stress relieving layer thickness up to 90mm thickness! Bore Cores Taken from Hungarian Highway!
Road Construction – Stress Reliefe Layer (SAMI) PGM and PGM-G Method Bore Cores Taken from Hungarian Highway!
Applications (1) Bituminous Overlays Hot Rolled Asphalt (2) Surface Dressing PGM 14 PGM-G & E Grades PGM 14 only
Typical Crack Growth Bituminous Overlay Bituminous Overlay Crack Growth PGM & PGM-G Thermal expansion and contraction Subbase
Increases the Life Time TenCate PGM & PGM-GStress Relief Layer (SAMI) Stress Concentration! Stress Reduction!
Working Procedures (1) Cleaning the road surface (2) Filling of the potholes and cracks (>3mm) with bitumen On highly damaged roads a levelling layer is recommended
Working Procedures (3) Tack Coat Spray Pour Bitumen or Emulsion Quantity >1.1 kg/m² Bitumen (PGM-G) Quantity >0.4 kg/m² Bitumen (PGM-G E) High Viscosity > 65% Bitumen Content (4) Paving Geocomposite or Paving Fabric Installation - Installation device (recommended) - no folds - no overlapping required
Working Procedures a) Bituminous Wearing Coarse • after the PGM & PGM-G installation • possibility of temporary trafficking b) Surface Dressing • After Installation of Geosynthetics • tack coat spray • - Application of chipping
(1) Working Procedures – Bituminous OverlaysInstallation of PGM & PGM-G products • Apply asphalt layer after the installation of PGM & PGM-G products • Pavers on tracks is recommended • Installation temperature between 120°C to 165°C, depending on layer thickness • If the tyres are sticking: Spread asphalt in the wheel tracks
(2) Working Procedures – Surface DressingInstallation of PGM • Application of tack coat to existing pavement installation of PGM; 2nd. application of tack coat 0,8 kg/m² emulsion • Volume of emulsion, amount and grading of chipping, in accordance with guidelines for surface dressing • Immediately after 1.chipping layer rolling necessary • In case of 2 or more chipping layers, a sufficient bonding is required between the layers • After 1-3 days test driving the unbounded chips has to be removed
Example of Surface Dressing(A143, Bungay Norfolk UK) Road Surface before treatment 6mm surface dressing being applied on PGM 14
Hot Rolled Asphalt (e.g. 4 or 5cm) is COSTLY! Project Introduction Mrozow/Poland July 2008 Surface Dressing with PGM14 Access Road on countryside Actual Problem
Requirement of Quality Paving GeocompositesPrevention of Reflective Cracking + Asphalt Reinforcement TC PGM-G Benefits Crack Relief (STR) Sealing (B) Reinforcement (R) Literature: EN 15381 Elongation of Asphalt Concrete approx. 0,1% 0°Grad approx.2% 20°Grad
Paving Geocomposites (E - Types)PGM-G30/30 E Rehabilitation of Asphalt Roads PGM-G50/30 E PGM-G100/100 E Elongation of Asphalt Concrete approx. 0,1% 0°Grad approx.2% 20°Grad
Functions according EN 15381 –Geotextiles and geotextile related productsR + STR + B R=reinforcement = reinforce the bituminous layer, stopping and controlling the cracking process STR= stress relief = function provided by a bitumen-saturated paving fabric (non-woven or purpose-built composite) which, when is properly installed between a road surface and a new asphalt overlay allows for slight differential movements two layers and thus provides stress relief, which delays or arrests crack propagation in the asphalt overlay B= interlayer barrier = function provided by paving fabrics, which act in conjunction with a bitumen layer as a barrier to the ingress of water and thus prevent or delay the deterioration of the pavement
SealingPermeability Conventional Method vs. PGM& PGM-G (140g/m² nonwoven) The non-woven works as Bitumen Storage. The sprayed bitumen will kept in place. Conventional constructions Water Permeability Reduction from 10-1 to 10-5mm/sec PGM Application Literature: Transportation Research Center by M. L. Marienfield and T. L.Baker
Vertical loading (amplitude 0.2 mm) Horizontal Frame loading (0,6 mm/h) 6 Overlay Crack Detektors ] PGM 14 m 5 c Crack Asphalt Concrete [ Base plate with PGM without PGM 4 h t Frame p 3 e d 2 k c a 1 r C Time [min] 0 100 200 300 400 500 600 Polyfelt PGM 14- Flexural Fatigue Test 1m
Steel Plate Steel Plate P P Applied Load: 890N Asphalt Type: AC20 Thickness: 5cm Beam: 7,5cmx7,5cmx61cm Rubber Rubber 50 25 Notch 3mm Notch 3mm Rubber Foundation Rubber Foundation ESAL =no of cycles in 1.000 PGM ESAL =no of cycles in 1.000 FatigueTest Data(prepared by Resource Int, Ohio) – at 20°C Result Fatigue Data: C-1 11.800 C-2 10.076 C-3 12.084 FEF - Applied Load: 890N Asphalt Type: AC20 Thickness: 5cm Beam: 7,5cmx7,5cmx61cm Product Type:PGM 14 Tack Coat: 0,9 kg/m² Result Fatigue Data: F-1 20.850 F-2 16.976 F-3 18.564 50 FEF 1,7 25
Steel Plate Steel Plate P P Rubber Rubber Notch 3mm Notch 3mm Rubber Foundation Rubber Foundation ESAL =no of cycles in 1.000 PGM PGM Fatigue Test Data (prepared by Resource Int, Ohio) – at 20°C Applied Load: 890N Asphalt Type: AC20 Thickness: 5cm Beam: 7,5cmx7,5cmx61cm Product Type:PGM 14 Tack Coat: 1,1 kg/m² Result Fatigue Data: F-4 24.826 F-5 31.637 F-6 29.387 FEF 2,6 50 25 Applied Load: 890N Asphalt Type: AC20 Thickness: 5cm Beam: 7,5cmx7,5cmx61cm Product Type:PGM 14 Tack Coat: 1,3kg/m² Result Fatigue Data: F-7 48.117 F-8 46.846 F-9 49.587 50 FEF 4,3 25 ESAL =no of cycles in 1.000
Analysis of the tests (Faculty Polytechnico Milano/Italy – Four Point Beam test 2008) Message 1 Message 2 Message 1: Cycle Increaseatthe same lossofelasticmodulus (%) Message 2: With same loadcyles an increaseofbearingcapacityof 25% will beachieved
Spraying of Tack coat Complete Bitumen Spraying required
Bituminous Overlays approx. 10cm lateral distance
Installation side by side laying (butt joint) ….ready for the asphalt layer application…
Installation of PGM 14 on Cement Stab. Layer - 3,5 cm SMA11 LKI (´05) - 12,0 cm BT32 LKI - TenCatePGM 14 - 1,9 kg/m² O70 K PM - Evaporation Protection - 30 cm Cement Stab.
Factors of success • Installation Support & Installation Equipment Manual Equipment for max 1,90m width (expandable) Equipment for max 3,80m Mounted on excavator, Bobcat, etc.
Factors of success • Usage of products which can get trafficked
2 Years Research Project - TU-Vienna Finalization of all tests by end of 2009 a) Installation of geosynthetic interlayers commencing April 2008(3 groups Geotextiles, Geocomposite, Geogrids & Conventional Section) b) Subsequently Trafficking for 3 month on the test area(Teerag Asdag in Vienna) c) Drilling of 350 bore cores on the site by end of June 2008 by “MAPAG” d) Start wedge splitting test of taken bore cores of the site in September 2008 by TU Vienna.
2 Years Research Project - TU-Vienna Group 1: function = stress absorbing membrane interlayer (SAMI) Group 2: function = Asphalt Reinforcement
Group 3: function = Geocomposite SAMI + Asphalt Reinforcement
WedgeSplitting Test [Tschegg 1986] • Fracture mechanic properties obtained • Cubes from Drilling cores • Interface (Geosynthetics) in the middle of the specimen • Splitting energy in the specimen, Starter notch crack control • FH = FM /(2tg(α/2)) … α=angle of wedge • FVsmall compared to FH
WST – Evaluation of results σNTS .... notch tensile strength [MPa] FH max ... max. splitting force [N] A ......... ligament area [mm²] Mb ....... bending moment [Nmm] Wy …... axial section modulus [mm³] GF .... spec. fracture energy [J/m²] A …... ligament area [m²] FH …. horizontal force [N] s ....... CMOD [m]
Fracture crack growth behavior • Reference: low energy fast crack growth • Non performing Interlayer: low resistance against crack growth • Well performing Interlayer: no crack growth • Geosynthetics takes over the force even the CMOD is more than2mm • fracture at -10°C, 0°C, +10°C
Large scale test pit Specimen Drilling core + interlayer
2 Years Research Project - TU-Vienna • Methods for the evaluation of the crack growth • Electrical Device • Optical Device • Acoustical crack evaluation Screenshoot Webcam
2 Years Research Project - TU-Vienna Cooling Equipment with in Integrated testing machine Test Equipment with Cooling box (Test Temperatures at -20°C, 0°C, +20°C)