Flores Geotechnical, based in Round Rock, teamed up with Applied Research Associates, Inc. (ARA) to help the Texas Department of Transportation's Laredo District with collecting pavement data for the assessment and improvement of 7 miles of Interstate 35. Heavy traffic from 18-Wheeled tractor trailers had damaged long sections of the north bound lane, resulting in rutting and surface roughness. They used non-destructive tests like Ground Penetrating Radar (GPR), Falling Weight Deflectometer (FWD), Dynamic Cone Penetrometer Testing (DCP), coring, soil borings, and laboratory tests.
GPR is a type of nondestructive testing that can provide a continuous profile of pavement conditions such as layer thicknesses, locations of defects such as stripping and subsurface moisture. FWD is a non-destructive method used to evaluate the structural capacity of the pavement and allows engineers to determine in-situ resilient modulus (stiffness) properties of the existing pavement layers and subgrade. Dynamic Cone Penetrometer Testing is a semi-nondestructive technique that provides insight into the subgrade thickness, and subgrade resilient modulus.
ARA, Flores's partner, started the investigation with GPR and FWD. Results helped choose core locations strategically, reducing the number in areas with suspected issues. They also took pictures along the entire segment to document surface conditions, such as patching and changes in pavement.
Flores, with Texas Geo Bore, LLC's help, completed the coring and borings, measuring asphalt and base thickness, testing for stabilizer, and classifying soil samples for sulfates, and performed DCP Tests. Soil samples were tested in Flores' AASHTO accredited laboratory following TxDOT and ASTM methods where applicable.
Flores managed the project including coordinating with TxDOT Area and District Pavement Engineers and providing traffic control services while the FWD and drilling and DCP crews were on the road.
This project happened through a statewide geotechnical contract Flores has with TxDOT. Currently, Flores is helping other TxDOT districts evaluate distressed pavements.