Evaluating the Traffic Speed Deflectometer (TSD) for network-level screening of pavements in Michigan

As state-highway agencies move toward data-driven pavement management, the Traffic Speed Deflectometer (TSD) has emerged as an alternative non-destructive testing (NDT) technology that allows for continuous pavement data collection at traffic speed without having the need for lane closures. Its’ usage focus has been researched mostly for flexible pavements, while its application for rigid and composite pavements remains largely unexplored. This study addresses the gap by developing a network-level screening framework for identifying strong to weak pavements in Michigan. The study suggests a mechanistic-based load conversion method utilizing Westergaard’s plate theory to determine the equivalent quasi-static falling weight deflectometer (FWD) load from TSD dual tires loading. Such approach of using equivalent quasi-static FWD load is consistent with the AASHTO procedures for determining the Portland cement concrete (PCC) elastic modulus and modulus of subgrade reaction (composite k-value). A key finding is the recommendation of a 1.25 correction factor that allows the backcalculated PCC elastic modulus to be closer to the in-situ static properties. Similarly, the study recommends using the SCI12 surface condition index and Area7 as the TSD indices for estimating the condition of PCC and subgrade support. The thresholds for these indices were determined based on Remaining Structural Life (RSL) to establish “Good”, “Fair”, and “Poor” conditions. An “interaction plot” is established to determine the condition of PCC and the subgrade support. A case study on Interstate 69 demonstrates how to use the TSD data for screening and project level evaluation.

Level thesis:degree_level

Master’s Degree

Year dc:date.issued

2026

Author dc:creator

• Khanal, Bipin

Advisor dc:contributor.advisor

• Hajj, Elie Y.

Committee members dc:contributor.committeemember

• Sebaaly, Peter E.
• Hand, Adam J.T.
• Panorska, Anna K.

• Backcalculation
• Network-Level Screening
• Remaining Structural Life
• Rigid Pavement Analysis & Design
• Traffic Speed Deflectometer
• TSD Indices

Language dc:language.iso

en_US, English

Repository record dc:identifier.uri

https://scholarwolf.unr.edu/handle/11714/11856

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/11856