‘Characterisation of Granular Materials Rut Resistance’ Austroads project TT1819 Pavement Technology Program Andrew Papacostas (VicRoads) Austroads Project Manager Austroads workshop – Wellington– 4 th December 2014

advisor to road authorities for technical input and solutions 2 Project objective –The purpose of the project is to maximise the use of available materials in road base construction, and reduce road agency costs, by developing effective methods for evaluating the performance of unbound granular materials. –Propose improved laboratory testing for rut resistance characterisation –Identify key material performance parameters to further develop material specifications

advisor to road authorities for technical input and solutions 3 Project TT1163 ‘Better basis for bases’ (Optimum Use of Granular Bases) Project background

advisor to road authorities for technical input and solutions 4  Development of a wheel-tracker for laboratory characterisation Report AP-R (Austroads 2010) Project background

advisor to road authorities for technical input and solutions 5 Project background Project TT1611 ‘Improved rut resistance characterisation’ (Austroads 2012)

advisor to road authorities for technical input and solutions 6 Project background Development of the wheel tracking testing procedures specimen preparation and sealing

advisor to road authorities for technical input and solutions 7 TT Two Main Research Components Laboratory Characterisation –Wheel-tracking (WT) –Repeated Load Triaxial Tests (RLT) Accelerated Pavement Austroads 2014 – Report AP-T267-14

advisor to road authorities for technical input and solutions 8 Accelerated Pavement Testing Component Test site: Dandenong South – VIC Indoor facility Experiments focused on granular base deformation

advisor to road authorities for technical input and solutions Pavements structure 9 Unbound granular base Stiff & not deforming support Cement treated crushed rock Unbound granular base 300 mm 150 mm Natural clay subgrade Re-used granular materials Stabilised clay including drainage layer 150 mm Sprayed seal 

advisor to road authorities for technical input and solutions Base Characteristics 10 Material Sample No. PI (wet prep.) OMC* (%) MDD* (t/m 3 ) Granite standard Hornfels standard – Granite increased plasticity Hornfels increased plasticity * modified proctor compaction (AS )

advisor to road authorities for technical input and solutions Pavements layout 4 lanes x 3 (12 m long test sites) 11 Lane no. Material (20mm well-graded crushed rock) 1 granite, low-plasticity 2 hornfels, low-plasticity 3 granite, increased plasticity 4 hornfels increased plasticity

advisor to road authorities for technical input and solutions ALF trafficking program Forecast 1.5 years of pavement trafficking, this equates to about 2½ million loading cycles –8,000 cycles per day –5 days per week –40 weeks operational per year 12 pavements –4 materials –3 replicates or different conditions Allows about 200,000 trafficking cycles per pavement 12

advisor to road authorities for technical input and solutions ALF loading conditions Objective: compare WT lab performance vs ALF performance –WT tests (average contact stress ≈ 600 kPa) –ALF: dual-tyre loads (11 R22.5)  Applied loading conditions: dual wheel (11R22.5 truck tyre) under 40kN Load wandering ± 0.5 m according to a pseudo normal distribution 13

advisor to road authorities for technical input and solutions 14 Wheel-tracking test for UGM Data processing 5 profiles along the wheel-path Number cycles  (-150, -75, 0, +75, +150 mm)

advisor to road authorities for technical input and solutions 15 WT data: mean deformation & rut depth Mean profile deformation (Calculated across the tyre nominal width) Maximum rut depth (Mathematical data processing)

advisor to road authorities for technical input and solutions Crushed hornfels (example) 16 Mean deformation Maximum rut depth Test terminated before 40,000 cycles

advisor to road authorities for technical input and solutions Moisture sensitivity: TT1163 materials 17 Rhyolite Hornfels Limestone Tuff

advisor to road authorities for technical input and solutions 18 WT.vs. ALF performance comparison ALF performance data (load = 60 kN on dual-wheel)

advisor to road authorities for technical input and solutions 19 WT.vs. ALF performance comparison ALF.vs. WT moisture conditions Hornfels Limestone Rhyolite Tuff

advisor to road authorities for technical input and solutions Trafficking results 20 Lane 1 Lane 2 Lane 3 Lane 4

advisor to road authorities for technical input and solutions Effect of moisture on pavement deformation % 4.2% 3.5% MC + 0.5% MC – 0.7% MC ~ 70% OMC ~ 60% OMC ~ 50% OMC

advisor to road authorities for technical input and solutions 22 Laboratory Characterisation Component Laboratory Characterisation –Main focus: Wheel-tracking –Repeated Load Triaxial Tests

advisor to road authorities for technical input and solutions 23 WT testing program Testing conditions –4 ALF materials –For each material DD = ALF pavm t DD MC = three levels (ALF MC) Similar program is planned under triaxial conditions –RLT (AGPT033) –Shear strength testing

advisor to road authorities for technical input and solutions 24 Moisture sensitivity data Preliminary results

advisor to road authorities for technical input and solutions 25 RLT preparation conditions Data collected –Australian & NZ context –International practice –Summary –Definition of the preparation conditions Compaction (modified proctor hammer) Compaction moisture content –MC < OMC vs OMC + dry-back Loading conditions –AGPT033 –Drained (undrained)

advisor to road authorities for technical input and solutions 26 Overall objective (principle) Laboratory Characterisation Wheel-tracking (WT) Accelerated Pavement