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/ Use of Recycled Plastics in Asphalt Pavement Year 2 https://rip.trb.org/View/1856848 Sat, 05 Jun 2021 17:21:20 GMT https://rip.trb.org/View/1856848 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 Multi-Span Lateral Slide Laboratory Investigation: Phase 1 https://rip.trb.org/View/1694791 Tue, 24 Mar 2020 12:48:21 GMT https://rip.trb.org/View/1694791 Continuing Toward Implementation of Performance Engineered Concrete Mixtures for Durable and Sustainable Concrete https://rip.trb.org/View/1672432 Wed, 11 Dec 2019 15:53:58 GMT https://rip.trb.org/View/1672432 SPR-4448: Central HMA Acceptance Lab Process Improvement Implementation Plan https://rip.trb.org/View/1660777 Tue, 22 Oct 2019 09:33:49 GMT https://rip.trb.org/View/1660777 Investigation of No. 10 Screenings for Subgrade Soil Improvement https://rip.trb.org/View/1602879 Thu, 02 May 2019 09:14:52 GMT https://rip.trb.org/View/1602879 Performance Characteristics of Modern Recycled Asphalt Mixes in Missouri, Including Ground Tire Rubber, Recycled Roofing Shingles, and Rejuvenators https://rip.trb.org/View/1594494 Sat, 23 Mar 2019 12:51:13 GMT https://rip.trb.org/View/1594494 Field Evaluation of Reinforced Concrete Repairs using Hydro-Demolition, Galvanic Cathodic Protection or Impressed Current Cathodic Protection https://rip.trb.org/View/1563447 Mon, 15 Oct 2018 09:31:31 GMT https://rip.trb.org/View/1563447 Validation of Gyratory Mix Design in Iowa Phase II https://rip.trb.org/View/1505439 Mon, 19 Mar 2018 11:52:51 GMT https://rip.trb.org/View/1505439 Implementation of Low Temperature Cracking Criteria in Iowa https://rip.trb.org/View/1503770 Fri, 02 Mar 2018 15:26:48 GMT https://rip.trb.org/View/1503770 Research for AASHTO Standing Committee on Highways. Task 412. Adjustments to the Superpave Volumetric Mixture Design Procedure for Selecting Optimum Asphalt Content https://rip.trb.org/View/1491277 Mon, 11 Dec 2017 20:09:59 GMT https://rip.trb.org/View/1491277 Developing Performance Specification for High Performance Concrete https://rip.trb.org/View/1486041 Fri, 20 Oct 2017 11:37:08 GMT https://rip.trb.org/View/1486041 SPR-4154: Continued Support of the Mobile Infrastructure Materials Testing Laboratory https://rip.trb.org/View/1441968 Wed, 04 Jan 2017 15:59:37 GMT https://rip.trb.org/View/1441968 PPRC14 SPE 4.52B: Microcracking for Cement Stabilized Layers: Phase 2 HVS & Field Testing https://rip.trb.org/View/1441819 Wed, 04 Jan 2017 10:53:27 GMT https://rip.trb.org/View/1441819 Short- and Long-Term Binder Aging Methods to Accurately Reflect Aging in Asphalt Mixtures https://rip.trb.org/View/1406906 Mon, 09 May 2016 10:10:38 GMT https://rip.trb.org/View/1406906