Research in Progress (RIP) https://rip.trb.org/ en-us Copyright © 2024. National Academy of Sciences. All rights reserved. http://blogs.law.harvard.edu/tech/rss tris-trb@nas.edu (Bill McLeod) tris-trb@nas.edu (Bill McLeod) Research in Progress (RIP) https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg https://rip.trb.org/ Synthesis Study of Costs and Trip Rates of Recent Household Travel Surveys https://rip.trb.org/View/2233697 Fri, 25 Aug 2023 13:51:09 GMT https://rip.trb.org/View/2233697 Lab Dielectric Measurement System for Asphalt Mixture Bulk Specific Gravity Determination https://rip.trb.org/View/1749087 mb) of compacted asphalt mixtures requires multiple equipment and weight measurements for different conditions which, along with the operator experience, influence the accuracy and variability of Gmb measurements. The use of a laboratory dielectric measurement system (LDMS) was explored in this study as an alternative procedure to the current AASHTO specifications for measuring Gmb. The LDMS measures the dielectric constant of a compacted asphalt concrete specimen using a ground penetrating radar (GPR) system. In Stage 1 of the project, a procedure to measure the laboratory dielectric value of a compacted asphalt concrete specimen was established. Asphalt mixtures with a range of aggregate and mixture properties (geology, nominal maximum aggregate size, binder type, RAP content, etc.) were collected. Compacted asphalt specimens of various specimen surface conditions and sizes were tested using the LDMS. The collected dielectric results were statistically analyzed to study dielectric measurement repeatability and reliability by grouping measurements at various orientations together and comparing them to all measurements of the corresponding asphalt specimen. Sensitivity analysis was also performed to study measurement accuracy and resolution for replicate dielectric measurements. It was determined that taking dielectric measurements at any 3 orientations 120 degrees apart (3 measurements total) yield repeatable dielectric measurements with acceptable accuracy. In Stage 2 of the project, a procedure to determine Gmb based on the laboratory measured dielectric value was developed. A select number of asphalt mixtures from Stage 1 work, along with their component materials (aggregates and RAP) were collected. The Al-Qadi Lahour Leng (ALL) model and the Hashin-Shtrikman (HS) model were investigated and analyzed to establish the relationship between Gmb and dielectric measurements. Based on the gathered data and statistical analyses performed in Stage 2, a procedure using the HS model and laboratory measured dielectric values of component materials was recommended to determine specimen Gmb.  The recommended procedure produces predicted values of Gmb from measured dielectric values that are within the acceptable range of two Gmb results in AASHTO T331 for most specimens evaluated. The final report is available. ]]> Wed, 04 Nov 2020 10:36:53 GMT https://rip.trb.org/View/1749087 Onboard Sensing, Analysis, and Reporting (OSAR): Expanded Field Demonstrations and Development of Associated Visual Aids https://rip.trb.org/View/1722130 Wed, 15 Jul 2020 12:56:03 GMT https://rip.trb.org/View/1722130 e-DNA for Aquatic Species https://rip.trb.org/View/1683236 Thu, 06 Feb 2020 13:33:39 GMT https://rip.trb.org/View/1683236 Examination of Engine to Engine PM Emissions Variability Using an ARP Reference Sampling and Measurement System https://rip.trb.org/View/1532752 Fri, 17 Aug 2018 11:41:18 GMT https://rip.trb.org/View/1532752 Non-Invasive Detection and Identification of Eastern Hellbender in Ohio Surface Waters Using Aquatic Environmental DNA (Phase 2) https://rip.trb.org/View/1505471 Tue, 20 Mar 2018 12:39:11 GMT https://rip.trb.org/View/1505471 DMask: A Reliable Identity Masking System for Driver Safety Video Data https://rip.trb.org/View/1370015 Wed, 23 Sep 2015 09:37:26 GMT https://rip.trb.org/View/1370015 Real-Time Quality Control Monitoring and Characterization of Aggregate Materials in Highway Construction using Laser Induced Breakdown Spectroscopy https://rip.trb.org/View/1336357 Mon, 29 Dec 2014 01:00:33 GMT https://rip.trb.org/View/1336357 Bioinjury Implications of Pre-crash Safety Modeling and Intervention https://rip.trb.org/View/1285233 Sat, 04 Jan 2014 01:00:20 GMT https://rip.trb.org/View/1285233