Below are brief descriptions of communications products recently developed by the Federal Highway Administration’s Office of Research, Development, and Technology. All of the reports are or will soon be available from the National Technical Information Service (NTIS). In some cases, limited copies of the communications products are available from FHWA’s Research and Technology (R&T) Product Distribution Center (PDC).

When ordering from NTIS, include the NTIS publication number (PB number) and the publication title. You also may visit the NTIS website at www.ntis.gov to order publications online. Call NTIS for current prices. For customers outside the United States, Canada, and Mexico, the cost is usually double the listed price. Address requests to:

National Technical Information Service
5301 Shawnee Road
Alexandria, VA 22312
Telephone: 703–605–6050
Toll-free number: 1–888–584–8332
Website: www.ntis.gov
Email: customerservice@ntis.gov

Requests for items available from the R&T Product Distribution Center should be addressed to:

R&T Product Distribution Center
Szanca Solutions/FHWA PDC
700 North 3rd Avenue
Altoona, PA 16601
Telephone: 814–239–1160
Fax: 814–239–2156
Email: report.center@dot.gov

For more information on R&T communications products available from FHWA, visit FHWA’s website at www.fhwa.dot.gov, the FHWA Research Library at https://highways.dot.gov/resources/research-library/federal-highway-administration-research-library (or email fhwalibrary@dot.gov), or the National Transportation Library at ntl.bts.gov (or email library@dot.gov).

Long-Term Pavement Performance (LTPP) Program Specific Pavement Studies (SPS) Development of Experiment Design: SPS-11 Asphalt Concrete Pavement Preservation Study

Publication Number: FHWA-HIF-18-063

Pavement preservation represents a proactive approach to maintaining and extending the life of existing highways. Research findings over the past few years prove that pavement preservation can be a cost-efficient approach to extend pavement's effective service life and improve safety and service condition.

This report documents the recommended experimental design for the Long-Term Pavement Performance (LTPP) SPS-11 Asphalt Concrete Pavement Preservation Study. Researchers designed the study to establish the impact of selected preservation treatments on pavement performance under different loading and environmental conditions through a field study of inservice pavements starting from construction of the preservation treatments under consideration. The experiment focused on determining the best time to apply a preservation treatment on asphalt concrete pavement.

The document is available to download at www.fhwa.dot.gov/publications/research/infrastructure/pavements/ltpp/18063/index.cfm.

Long-Term Pavement Performance (LTPP) Program Specific Pavement Studies (SPS) Development of Experiment Design: SPS-12 Portland Cement Concrete Pavement Preservation Study

Publication Number: FHWA-HIF-18-064

This report documents the recommended experimental design for the LTPP study, SPS-12 Portland Cement Concrete Pavement Preservation. Researchers designed the study to establish the impact of selected preservation treatments on pavement performance under different loading and environmental conditions through a field study of inservice pavements starting from construction of the preservation treatments under consideration.

The underlying concept of this experiment was to apply the same preservation treatment, at different times, on the same pavement structure to determine the effectiveness of a single application of a treatment as a function of pavement condition and time. The study will enable development and implementation of important pavement preservation products and tools, such as the addition of pavement preservation considerations to the American Association of State Highway and Transportation Officials' (AASHTO) Mechanistic-Empirical Pavement Design Guide and associated software. The experiment and this project report can be adopted and adapted by interested highway agencies to achieve the stated benefits.

The document is available to download at www.fhwa.dot.gov/publications/research/infrastructure/pavements/ltpp/hif18064/index.cfm.

Lightweight Concrete: Transfer and Development Length of Prestressing Strands

Publication Number: FHWA-HIF-19-018

Advancements in concrete materials have led to significant enhancements in the performance of lightweight concrete. However, decades-old performance perceptions continue to hinder wider use of lightweight concrete.

From 2007 through 2015, FHWA conducted a long-running experimental study to investigate the structural performance of modern lightweight concretes. The overall study engaged the academic, public sector, and private sector communities to compile the body of knowledge on lightweight concrete while also conducting nearly 100 full-scale structural tests on lightweight concretes.

This report presents the results of transfer length measurement and development length tests on prestressed girders made with high-strength, lightweight concrete, as well as a compilation of data available from the literature. It also provides potential revisions to the AASHTO Load and Resistance Factor Design Bridge Design Specifications, with a focus on transfer and development length of prestressing strands in lightweight concrete.

The document is available to download at www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge/19018/index.cfm.

Simulator Assessment of Alternative Lane Grouping at Signalized Intersections

Publication Number: FHWA-HRT-19-025

FHWA is focused on improving highway design by increasing knowledge of how intersection design affects operational efficiency and safety. Two intersection configurations designed to increase capacity without adding lanes are the dynamic reversible left-turn lane at diamond interchanges and the contraflow left-turn lane at signalized intersections. FHWA researchers explored these configurations in the project "Simulator Assessment of Alternative Lane Grouping at Signalized Intersections." This project consisted of two studies, both conducted in the Highway Driving Simulator at FHWA's Turner-Fairbank Highway Research Center (TFHRC), which assessed driver behavior and comprehension in response to signs and symbols used to convey reversible-lane operations.

Findings show that signs and markings used in both studies will work well in a real-world environment. The publication includes recommendations for additional and modified signs and markings on the approach sides of dynamic reversible left-turn and contraflow left-turn intersections to improve comprehension and comfort of drivers who may see opposing traffic in their lane while waiting for a green signal.

This report will be of interest to engineers, planners, and transportation professionals concerned with implementing signs and pavement treatments for alternative intersections and responsible for highway design and public safety.

The document is available to download at www.fhwa.dot.gov/publications/research/safety/19025/.

Formation Factor Demystified and Its Relationship to Durability

Publication Number: FHWA-HRT-19-030

Electrical resistivity is a property that indicates the material's resistance to the passage of electrical charges at a defined temperature, and many transportation departments and commercial labs use concrete resistivity in durability testing. However, the formation factor can provide a better measure of durability by including consideration of the concrete pore volume and pore connectivity.

This TechBrief aims to help practitioners understand concrete electrical resistivity—how it is measured, its limitations, and its relationship with durability—and explores the use of the formation factor as an alternative for testing durability. The publication discusses how the formation factor is obtained, the options to determine the pore solution resistivity (one of the necessary inputs for calculation of the formation factor), and the "bucket test," an alternative to simplify the process.

The TechBrief highlights research currently being conducted at FHWA's TFHRC. Researchers are working on closing the gaps for the reliable determination of the formation factor, focusing on aspects related to pore solution resistivity.

The document is available to download at www.fhwa.dot.gov/publications/research/infrastructure/pavements/19030/index.cfm.