Chapter 11: Forensics


Section 1: Overview

Despite advancements in pavement technology in past decades, premature failures and chronic pavement distresses continue to occur. Although improvements have been made to construction specifications, equipment, and construction processes, poor quality construction can occur due to a number of complex and sometimes competing variables such as:

  • reduced inspection staffing
  • employee turn over
  • fluctuations in levels of experience inspectors and project managers
  • incompatibilities between new admixtures and construction materials
  • implementation of new technologies and construction methods
  • environmental constraints and recycled materials
  • other issues unforeseen during design and construction phases.

To prevent, and to reduce the probability of premature pavement failures and poor long term pavement performance, the root causes of these problems have to be identified. It is a challenging task to determine the causes of pavement failures. In conducting forensic studies, a thorough review and analysis of existing quality construction records and tests, nondestructive testing like ground penetrating radar (GPR) and the falling weight deflectometers (FWD) are essential to identify problematic areas and probable causes. Field testing such as dynamic cone penetration (DCP), portable FWD, dirt seismic pavement analyzer (DSPA), coring, trenching, and laboratory testing are also conducted to validate/confirm the initial hypothesis. From time to time, the outcomes from forensic studies have been used to validate/change/modify the existing design plan, and to resolve the disputes involving construction claims. In general, the forensic study should be completed 3 months after receiving the request.

For routine technical assistance, consult previous chapters. These types of requests for technical assistance are informal and are best made as early as possible during construction so as to allow maximum opportunity to correct problems, prevent premature pavement failures, and to allow time for appropriate contract administration.

Requests for Forensics Review and Reports (FR&R): After a project has been finally inspected and accepted by TxDOT, and the contractor has been released from contractual requirements, a FR may be requested by the districts/others. Premature pavement failures 0 – 5 years after the time of TxDOT acceptance of the project would likely be good candidates for FR&R.

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