Test Specifications for SPST and HWTT

US Transportation Collection2019PDFTech ReportWalubita, Lubinda F.Nyamuhokya, TitoLee, Sang IckTexas A&M Transportation InstituteTexas. Dept. of Transportation. Research and Technology Implementation OfficeUnited States. Department of Transportation. Federal Highway AdministrationTexas A&M Transportation InstituteUnited StatesFlexible pavementsHot mix asphaltMix designRuttingShear strainShear strengthShear testsSpecificationsTest proceduresHamburg Wheel Tracking DeviceHamburg Wheel Tracking TestHWTTSimple Punching Shear TestSPST5-6744-01-P15-6744-01This document is divided into two major parts: Part A and B. Part A documents some proposed modifications to the Hamburg wheel-tracking test (HWTT) and Tex 242-F test procedure, whereas Part B documents the proposed tentative specification and test procedures for the simple punching shear test (SPST). For Part A (HWTT specification), the major modification is in Section 6.5 where the procedure to handle mixtures at higher HWTT test temperatures is described. TxDOT Project 5-6744-01 found most hot mix asphalt (HMA) mixtures fail rapidly when subjected to higher HWTT temperatures (60\ub0C). Nevertheless, those that survive require a closer look onto the response rutting plots and determination if adjustments are needed as explained in Section 6.5. Part B is a tentative proposed draft specification for SPST testing. The major output of this SPST protocol are HMA shear strength, shear strain, shear modulus, shear strain energy, and shear strain energy index. Of all these SPST parameters, only shear strength and shear strain energy index were found to have a good correlation with field rutting and HWTT testing (1, 2, 3).125