Status of the first experiment at the PaveLab

Transcription

1 Status of the first experiment at the PaveLab Fabricio Leiva-Villacorta, PhD Jose Aguiar-Moya, PhD Luis Loria-Salazar, PhD August 31 st, 215

2 Research Philosophy NANO MICRO MACRO FULL SCALE

3 Phase I Experiment 4 Different pavement structures, 8 sections Compare Asphalt concrete thicknesses Granular vs. cement treated base Evaluate construction practices Painting evaluation under tropical climate

4 Test Section AC1 AC2 AC3 AC4 Thickness, cm CTB GB GB CTB Thickness, in Real pavement

5 Phase I Experiment Sifón-La Abundancia

6 Instrumentation Laser profiler Pavement Strain Transducers (PAST) Soil Pressure Transducers (SOPT) Multi-Depth Deflectometer (MDD) Road Surface Deflectometer (RSD) Thermocouples

7 Gauge Array 3 cm 6 cm 9 cm MDD Thermocouple MDD Section Length = 6. m GB/CTB Subbase Subgrade

8 Test Settings 2, bi-directional load repetitions per day Carriage speed: 1 km/hr Applied load: 4, 6, 7, 8 kn Test tire: Dual 11R22-5 Wheel wandering: 1 mm Dry condition 23/7

9 Facility improvements

10 Material Properties Granular and CTB Property Subgrade Subbase Base Base for CTB CTB Wopt (%) gd max (kg/m 3 ) LL PI 16 NP NP CBR, % Pend. 35 kg/cm2 QC Specs NMAS, mm 19 AC, % 4.9 VMA 14.9 Min 14% VFA % Estability, Kg 1482 Min 8 Flow cm/1 DP Sieve Passing, % Specs 25.4 mm mm mm mm N N N N N N

11 FWD. Sensor Location (mm) FWD Deflection (mm E -2) AC1 AC2 AC3 AC4 Thickness, cm CTB GB Test Section AC1 AC2 AC3 AC4 GB Layer M (MPa) M (ksi) CTB Base Subbase 14 2 Subgrade 7 1 CTB Thickness, in

12 Laser Profile MDD s

13 Permanent Deformation-Laser 14. Permanent deformation, mm AC1 AC4 AC2 AC MESALs Average deformation (entire section) Thickness, cm Test Section AC1 AC2 AC3 AC4 1 2 CTB GB GB CTB Thickness, in

14 IRI IRI (m/km) AC1 AC4 AC2 AC3 Average of wheelpath MESALs Thickness, cm Test Section AC1 AC2 AC3 AC4 1 2 CTB GB GB CTB Thickness, in

15 subgrade Pressure, kpa AC1 AC2 AC MESALS AC3 pressure cell did not work Thickness, cm Test Section AC1 AC2 AC3 AC4 1 2 CTB GB GB CTB Thickness, in

16 MDD s 3 cm 6 cm 9 cm MDD Thermocouple MDD.5 Section Length = 6. m Deflection, mm mdd1- mdd1-18 mdd1-45 mdd1-7 mdd2-6 mdd2-3 mdd2-6 mdd2-9 Distance, m

17 Max. 4 kn - MDDs MDD Surface Deflection, mm AC1 AC4 AC2 AC MESALS Surface MDD Subgrade Deflection, mm AC1 AC4 AC2 AC MESALS Thickness, cm Subgrade Test Section AC1 AC2 AC3 AC4 CTB GB GB CTB Thickness, in

18 AC1 MDD Backcalculaded Layer Moduli Backcalulated Modulus, MPa M1 M2 M3 C Repetitions Estimated Deflection, mm Deflection Equality y = 1.16x R² = Measured Deflection, mm-3 E SR σ d C MPa =.1 Average n value = -.4 n 4 kn CR-ME

19 RSD-AC1 4 kn 3 cm 6 cm 9 cm 1 cm RSD N1 RSD N2 RSD S1 MDD MDD RSD S2 Deflection, mm N1 S1 N2 S Repetitions Construction variability!!!

20 RSD-AC4 1 1 Backcalculated Modulus, MPa CTB G SG MESALs Backcalculated Modulus, MPa CTB G SG MESALs 2 different locations along the center line

21 Strain Transducers Longitudinal Transverse 4 3 Longitudinal Transverse Microstrain 2 1 MicroStrain Distance, m Distance, m 2k rep. 1M rep. 4 kn

22 Strain Transducers Microstrain Longitudinal Transverse MESALS AC2 Water added to surface 4 kn

23 AC2

24 Strain Transducers Microstrain Evidence of fatigue cracking Longitudinal Transverse MESALS AC3 4 kn

25 Fatigue cracking AC3

26 Just over 5 Million ESALs Test section Repetitions ESALS 1 AC AC AC AC3* 1 24 * * *Until August 215

27 Deflection Analysis Initial state Sensor Location, mm Surface Modulus, MPa Deflection, mm FWD RSD MDD Sensor Location, mm FWD RSD MDD 5 2 Captures non-linear behavior of the lowers layers.

28 Deflection Analysis Failure State Sensor Location, mm Surface Modulus, MPa Deflection, mm FWD RSD MDD Sensor Location, mm FWD RSD MDD times higher More intensified non-linear behavior of the lowers layers. Exhibits the presence of the test pit concrete support layer (shallow rigid layer).

29 Lab. Characterization APA (AASHTO TP 63) HWT (AASHTO T324) FN (AASHTO TP 79-11) Sample Plant Produced Lab Prepared % Air Voids PD, mm % Air Voids PD, mm 58 C 52 C 46 C Sample TSR (AASHTO T283) Mr (AASHTO TP31-96/ASTM 4123) 5 C, 25 C, 4 C, 1 Cicle 3 Cicles 6 Cicles % Air Voids MPa MPa MPa Plant Produced Lab Prepared Repetitions Plant 3 C Plant 2 C Plant 1 C Lab 3 C Lab 2 C Lab 1 C 4PBB Test (AASHTO T321) Strain

30 Transfer functions Perm. Def. Fatigue Perm. Def. Gran. Base Perm. Def. Subgrade εε pp εε rr = e TT NN.355 NN ff = e (εε) ee.94tt εε pp = 1 4,998 NN,69 σσ 1,687 dd σσ,77 3 %ww 1,881 εε pp = 1 32,954 NN,4 σσ 2,41 dd σσ,421 3 %ww 16,983 Lab developed models are being calibrated with HVS results

31 Linked to software development

32 FUTURE Climatic Condition Chamber -Infrared + UV: Temperature + aging - Raining system moisture - Water table simulation

33 Summary Increase in Deflections Increase in vertical stress Increase in horizontal strain Cumulative damage Visible low severity cracks (fatigue) within effective section for AC2, AC3 (granular base). Cracking pattern initiates with transverse 3 cm, finally blocks are formed

34 Thank You!

35 APT 216 Important dates 1. October 9, 215: Deadline for submission of full paper for peer review 2. January 15, 216: Comments, notification of acceptance/rejection of full paper 3. March 11, 216: Submission of full, revised paper September 19-21, 216: APT 212 Conference