Data Collection for Determining Pavement Condition • • • • • Friction Profile Rut Depth Structure Distress identification

Friction Determination • Importance – Inadequate friction leads to higher number of crashes – Required to provide a safe road – Can be used to evaluate materials-AWI – Evaluated as • Locked Wheel • Spin Up Test • Surface Texture Measurement

Friction-Locked Wheel • ASTM 261 – Standard Tire – Water on surface – 40 MPH

Friction tester- Locked Wheel

Friction Tester Spin up • Wheel Lowered at 40 MPH – Friction force=torque/tire radius – f= Friction Force / Weight Better then Locked Wheel as less equipment is required

Spin Up Friction Tester

Road Surface Analyzer • • • • • • • A laser-based profiler using an accelerometer established inertial reference.

ROSAN measures texture and longitudinal pavement profile at highway speeds.

Texture Analysis - Determination of Mean Profile Depth Smoothness Analysis - 􀂾 Roughness Analysis - Determination of International Roughness Index (IRI) & Ride Number (RN), using ASTM E 950 & E 1926

Road Surface Analyzer

Roughness Measuring Rod and Level Dipstick profiler Road roughness Meter Profiling Devices

Roughness Measurement • • Present Serviceability Rating (PSR) – Based on ride quality defined by observer – Values from 1-5 International Roughness Index – Based on Average Rectified Slope (ARS) determined from vehicle accumulated suspension motion divided by the distance m/km – IRI= 1000*ARS

PSR

 5

e

 0.18(

IRI

)

Dipstick Analyzer •

Operation The Dipstick Road Profiler stands on two support legs.

The operator simply "walks" the Dipstick along a survey line alternately pivoting the instrument about each leg. Two digital displays show the elevation difference between the Dipstick's two support legs. Audible and visual signals alert the operator when each elevation difference reading is measured and automatically recorded.

Profilograph

Profiling Devices • • • • Straight Edges Low Speed Systems Inertial Reference Systems Can determine – Transverse Profile – Longitude Profile – Pavement Texture

Ames Engineering LISA

Laser RST Road Roughness Measurement

Rut Depth • • Uses many of the Standard Road Profilers Uses transducers to measure differences in elevation between wheel paths and center of road

Rut Depth

Distress Surveys • • • Automatic and Continous High Speed Digital Images Used At Speeds Up to 60 MPG

Dynatest Video Distress Vehicle

Structural Evaluation • • • • Falling Weight Deflectometers Dynaflect Dynamic Force Generator Benkleman Beam-Deflection Basin Ground Penetrating Radar

Structural Test Falling Weight Deflectometer

Dynaflect Dynamic Deflection System

Benkleman Beam Ground Deflection

Roadscan Ground Penetrating Radar