Superpave In-Situ Stress Strain Investigation
Field Measurements
Dynamic Measurements
A very important part of the SISSI project is to measure pavement response under different loading conditions. This dynamic response of the pavement under moving loads is simply referred to as “dynamic measurements”. The dynamic measurements are made by closing the driving lane to public traffic and trafficking the test section with PTI instrumented tractor/trailer. Successive runs are made with two different load configurations and three different speeds. Dynamic measurements from the load-induced signals (strain-gages, pressure cells, deflectometers, etc.) are collected through the data acquisition system connected to the datalogger box. These measurements are repeated seasonally.
Environmental Measurements
Environmental measurements, sometimes referred to as static measurements, deal with data from thermocouples (temperature measurements), resistivity probes (frost depth measurements), and time-domain reflectometers (moisture content measurements). These data do not depend upon traffic induced signals but are indicative of non-traffic associated response. These measurements are acquired on different schedules according to the type of measurement, and in accordance with the instrumentation plan.Tractor/Trailer
The tractor/trailer is loaded with heavy concrete blocks. The blocks could be moved back and forth to provide different load configutations and different loads on the rear and front axles.
