Evalution of Hot Mix Asphalt Moisture Sensitivity Using the Nottingham Asphalt Test Equipment, July 2005

Moisture sensitivity of Hot Mix Asphalt (HMA) mixtures, generally called stripping, is a major form of distress in asphalt concrete pavement. It is characterized by the loss of adhesive bond between the asphalt binder and the aggregate (a failure of the bonding of the binder to the aggregate) or by a softening of the cohesive bonds within the asphalt binder (a failure within the binder itself), both of which are due to the action of loading under traffic in the presence of moisture. The evaluation of HMA moisture sensitivity has been divided into two categories: visual inspection test and mechanical test. However, most of them have been developed in pre-Superpave mix design. This research was undertaken to develop a protocol for evaluating the moisture sensitivity potential of HMA mixtures using the Nottingham Asphalt Tester (NAT). The mechanisms of HMA moisture sensitivity were reviewed and the test protocols using the NAT were developed. Different types of blends as moisture-sensitive groups and non-moisture-sensitive groups were used to evaluate the potential of the proposed test. The test results were analyzed with three parameters based on performance character: the retained flow number depending on critical permanent deformation failure (RFNP), the retained flow number depending on cohesion failure (RFNC), and energy ratio (ER). Analysis based on energy ratio of elastic strain (EREE ) at flow number of cohesion failure (FNC) has higher potential to evaluate the HMA moisture sensitivity than other parameters. If the measurement error in data-acquisition process is removed, analyses based on RFNP and RFNC would also have high potential to evaluate the HMA moisture sensitivity. The vacuum pressure saturation used in AASHTO T 283 and proposed test has a risk to damage specimen before the load applying.

Monitoring of the Launched Girder Bridge over the Iowa River on US 20, March 2004

The objective of the study presented in this report was to document the launch of the Iowa River Bridge and to monitor and evaluate the structural performance of the bridge superstructure and substructure during the launch. The Iowa Department of Transportation used an incremental launching method, which is relatively unique for steel I-girder bridges, to construct the Iowa River Bridge over an environmentally sensitive river valley in central Iowa. The bridge was designed as two separate roadways consisting of four steel plate girders each that are approximately 11 ft deep and span approximately 301 ft each over five spans. The concrete bridge deck was not placed until after both roadways had been launched. One of the most significant monitoring and evaluation observations related to the superstructure was that the bottom flange (and associated web region) was subjected to extremely large stresses during the crossing of launch rollers. Regarding the substructure performance, the column stresses did not exceed reasonable design limits during the daylong launches. The scope of the study did not allow adequate quantification of the measured applied launch forces at the piers. Future proposed esearch should provide an opportunity to address this. The overall experimental performance of the bridge during the launch was compared with the predicted design performance. In general, the substructure design, girder contact stress, and total launching force assumptions correlated well with the experimental results. The design assumptions for total axial force in crossframe members, on the other hand, differed from the experimental results by as much as 300%.

Report Letter for Iowa State University of Science and Technologies various bond and note agreements, September 29, 2006

State University Audit Report - Report Letter

Evaluation of a Bridge Constructed using High Performance Steel, May 2006

Of the approximately 25,000 bridges in Iowa, 28% are classified as structurally deficient, functionally obsolete, or both. Because many Iowa bridges require repair or replacement with a relatively limited funding base, there is a need to develop new bridge materials that may lead to longer life spans and reduced life-cycle costs. In addition, new and effective methods for determining the condition of structures are needed to identify when the useful life has expired or other maintenance is needed. Due to its unique alloy blend, high-performance steel (HPS) has been shown to have improved weldability, weathering capabilities, and fracture toughness than conventional structural steels. Since the development of HPS in the mid-1990s, numerous bridges using HPS girders have been constructed, and many have been economically built. The East 12th Street Bridge, which replaced a deteriorated box girder bridge, is Iowa’s first bridge constructed using HPS girders. The new structure is a two-span bridge that crosses I-235 in Des Moines, Iowa, providing one lane of traffic in each direction. A remote, continuous, fiber-optic based structural health monitoring (SHM) system for the bridge was developed using off-the-shelf technologies. In the system, sensors strategically located on the bridge collect raw strain data and then transfer the data via wireless communication to a gateway system at a nearby secure facility. The data are integrated and converted to text files before being uploaded automatically to a website that provides live strain data and a live video stream. A data storage/processing system at the Bridge Engineering Center in Ames, Iowa, permanently stores and processes the data files. Several processes are performed to check the overall system’s operation, eliminate temperature effects from the complete strain record, compute the global behavior of the bridge, and count strain cycles at the various sensor locations.

Academic Building Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statements and Supplementary Information, June 30, 2006

State University Audit Report

Dormitory and Dining Services Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statements and Supplementary Information, June 30, 2006

State University Audit Report

Hilton Coliseum Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statements and Supplementary Information, June 30, 2006

State University Audit Report

Recreational Facility Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statement and Supplementary Information, June 30, 2006

State University Audit Report

Student Health Facility Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statement and Supplementary Information, June 30, 2006

State University Audit Report

Utility System Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statements and Supplementary Information, June 30, 2006

State University Audit Report

Telecommunications Facilities Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statements and Supplementary Information, June 30, 2006

State University Audit Report

Parking System Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Reports, Basic Financial Statements and Supplemental Information, June 30, 2006

State University Audit Report

Indoor Multipurpose Use and Training Facility Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statements and Supplementary Information, June 30, 2006

State University Audit Report

Regulated Materials Facility Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statement and Supplementary Information, June 30, 2006

State University Audit Report

Memorial Union Revenue Bond Funds, Iowa State University of Science and Technology, Independent Auditor's Report, Basic Financial Statements and Supplementary Information, June 30, 2006

State University Audit Report