Engineering Commons^™

Research On High-Rap Mixtures With Rejuvenator - Field Implementation, Nitish R. Bastola, Mahdieh Khedmati, Hamzeh Haghshenas

Nebraska Department of Transportation: Research Reports

The use of Rejuvenating Agents (RAs), as Recycled Asphalt Pavement (RAP) modifiers, has been increasing over the past years. However, the field performance of asphalt mixtures containing high-RAP materials and modified with RAs has raised some concerns regarding the long-term performance of RAs. This study evaluated the laboratory and field performance of high-RAP mixtures with and without bio-oil RA. Three sets of plant-produced specimens were collected: 1) laboratory-compacted; 2) field-compacted and cored after paving; and 3) field-compacted and cored after one and two years. The Hamburg Wheel Tracking (HWT) test was used to evaluate the specimens' resistance to rutting and …

Design And Detailing Of Cast-In-Place And Precast Concrete Approach Slabs, George Morcous, Mostafa Abo-Elkhier

Nebraska Department of Transportation: Research Reports

Approach slab is a structural concrete slab that spans from the backwall of the abutment (i.e. end of the bridge floor) to the beginning of the paving section. The purpose of the approach slab is to carry the traffic loads over the backfill behind the abutments to avoid differential settlement that causes bumps at the bridge ends. Cast- in-place concrete approach slab is the current practice in US with various spans, reinforcement, thicknesses, joints, and concrete covers. NDOT has observed premature cracking in a significant number of approach slabs, which could result in a shorter service life and costly repairs/replacements …

Research And Education For Optimizing The Development And Implementation Of An Unmanned Aircraft Program At The Nebraska Department Of Transportation, Wayne Woldt, Jon Starr, Christopher M. U. Neale

Nebraska Department of Transportation: Research Reports

This report describes the development and implementation of an Unmanned Aircraft System Program at the Nebraska Department of Transportation (NDOT). The project involved the selection and purchase of appropriate UAS and imaging systems for NDOT, education and training for NDOT personnel with classroom and hands-on operation of UAS with the goal of obtaining proficiency and pilot licenses. In addition, the development of policy for the use of UAS within NDOT was accomplished as well as standard operating procedures (SOP) documentation and the development of example case studies of interest to NDOT using the purchased systems and technology.

Low-Cost Modal Identification Sensors For Bridge Field Testing, Daniel Linzell, Saaed Eftekhar Azam, Samira Ardani, Ahmed E Rageh

Nebraska Department of Transportation: Research Reports

This report provides a framework for experimental load rating of bridges via inclusion of low-cost dynamic sensors and dynamic tests. Currently 25% of the bridges in Nebraska are posted for live load. According to the National Bridge Inventory (NBI) in 2012, 93% of all postings in the US were based analytical load ratings, 7% were posted using field evaluation and engineering judgement, and 1% were posted using experimental load rating methods.

Instrumentation costs and traffic interruptions can be problematic when load testing is necessary to accurately assess in-situ bridge live load capacity. Recent advances in (i) sensing technology and (ii) …