A Protocol for the establishment and operations of LTPP sections

Prepared for Gautransby CSIR, Transportek

Background

LTPP programmes developed to support the analysis of pavement performance leading to improved engineering tools for design, construction and management

Current LTPP programmes focus on performance models for PMSs

Needs to be a link to APT for greater confidence in interpreting APT results

Background cont..

In SA financial constraints have prevented LTPP test sections being linked to pavement performance under APT

LTPP sections have been developed on an ad hoc basis or as part of calibration sections

Renewed interest worldwide in linking APT to LTPP

Background cont..

For reliable models and design specs, it is imperative that data collected during LTPP programmes are reliabe and consistent with data collected during APT

Protocol already exists for establishment and operations of HVS test sections

Protocol required for LTPP to provide a consistent approach

Structure of Protocol

Linking LTPP to HVS data collection Management and responsibilities Site location and establishment

Data collection Reporting criteria

Minimum measurement requirements

Property LTPP HVS Difference

Visuals Mod TMH 9/HDM calib guide

Description of cracks

TMH-9 standard with added info on cracks

Trans profile Straight edge & wedge/electronic straight edge

Laser profilometer Full lane too wide for laser prof

Long profile Calibrated profiometer

Straight edge LTPP section too long for straight edge

Deflection RSD, FWD RSD FWD used routinely in Gautrans

Perm def MDD MDD

DensityDual probe strata gauge

Dual probe strata gaugeM/C Grav m/c used for

calibration

Pvmnt Temp Temp buttons Temp buttons

Traffic W-i-M HVS

Weather details Weather station Weather station

LTTP Staff Organisation Chart

Project Director

Project Manager

Database manager

Technician’s Assistant (s)

Field Technician

Road Authority/Agency

In-house or service provider

Proposed layout of LTPP sections

A 1 2 3 4 5 B 6 7 8 9 10 C

<20m> 5 x 15m 10m

5 x 15m <20m>

Not to scale

200 m – full lane width

•HDM calibration sections 500 m long covering entire road width

•Detail provided on instrumentation, markings and measurement points

Data collection

Monitoring every 6 months in May and October or when failure occurs

Sampling only from panels A, B and C or if failure occurs in other panels

Recommendations on reinstatement of test pits given to ensure impermeability

Monitoring standards given for: Visual assessment Transverse profile Longitudinal profile Density and M/C DCP Environment Deflection Permanent Deformation Traffic

Laboratory testing

Essential that material properties at the time of construction (or initiation of section) are fully recorded for comparison over time

As built records may not give sufficient detail Testing programme initiated at the following

intervals: Pre-construction/rehabilitation Post construction/rehabilitation In service (approx half-way through the design life of

section) Rehabilitation/end of service

Details of all recommended tests given in the document

Reporting of results

All field monitoring and test data checked by field technician and then PM before sending to the Database Manager

Any lab results sent with field data 1st level analysis carried out after each monitoring 2nd level analysis every 2 years to include:

An evaluation of the structural behaviour The identification of any extraneous effects The development and refinement of performance prediction

models On HVS/LTPP sections, the relationship between LTPP and

HVS performance for similar traffic levels