Quantitative Mapping of Waterways Characteristics at Bridge Sites, TR-569, 2008

Iowa state, county, and city engineering offices expend considerable effort monitoring the state’s approximately 25,000 bridges, most of which span small waterways. In fact, the need for monitoring is actually greater for bridges over small waterways because scour processes are exacerbated by the close proximity of abutments, piers, channel banks, approach embankments, and other local obstructions. The bridges are customarily inspected biennially by the county’s road department bridge inspectors. It is extremely time consuming and difficult to obtain consistent, reliable, and timely information on bridge-waterway conditions for so many bridges. Moreover, the current approaches to gather survey information is not uniform, complete, and quantitative. The methodology and associated software (DIGIMAP) developed through the present project enable a non-intrusive means to conduct fast, efficient, and accurate inspection of the waterways in the vicinity of the bridges and culverts using one technique. The technique combines algorithms image of registration and velocimetry using images acquired with conventional devices at the inspection site. The comparison of the current bridge inspection and monitoring methods with the DIGIMAP methodology enables to conclude that the new procedure assembles quantitative information on the waterway hydrodynamic and morphologic features with considerable reduced effort, time, and cost. It also improves the safety of the bridge and culvert inspections conducted during normal and extreme hydrologic events. The data and information are recorded in a digital format, enabling immediate and convenient tracking of the waterway changes over short or long time intervals.

Concrete Pavement Mixture Design and Analysis (MDA): Application of a Portable X-Ray Fluorescence Technique to Assess Concrete Mix Proportions , TPF-5(205), 2012

Any transportation infrastructure system is inherently concerned with durability and performance issues. The proportioning and uniformity control of concrete mixtures are critical factors that directly affect the longevity and performance of the portland cement concrete pavement systems. At present, the only means available to monitor mix proportions of any given batch are to track batch tickets created at the batch plant. However, this does not take into account potential errors in loading materials into storage silos, calibration errors, and addition of water after dispatch. Therefore, there is a need for a rapid, cost-effective, and reliable field test that estimates the proportions of as-delivered concrete mixtures. In addition, performance based specifications will be more easily implemented if there is a way to readily demonstrate whether any given batch is similar to the proportions already accepted based on laboratory performance testing. The goal of the present research project is to investigate the potential use of a portable x-ray fluorescence (XRF) technique to assess the proportions of concrete mixtures as they are delivered. Tests were conducted on the raw materials, paste and mortar samples using a portable XRF device. There is a reasonable correlation between the actual and calculated mix proportions of the paste samples, but data on mortar samples was less reliable.

Quantitative X-Ray Diffraction Measurements by Fast Scanning, HR-111

Two goals were pursued in this research: first, to evaluate statistically some effects of sample preparation and instrument geometry on reproducibility of X-ray diffraction intensity data; and second, to develop a procedure for finding minimum peak and background counting times for a desired level of accuracy. The ratio of calcite to dolomite in limestones was determined in trials. Ultra-fine wet grinding of the limestone in porcelain impact type ball mill gave most consistent X-ray results, but caused considerable line broadening, and peaks were best measured on an area count basis. Sample spinning reduced variance about one third, and a coarse beam-medium detector slit arrangement was found to be best. An equation is developed relating coefficient of variation of a count ratio to peak and background counts. By use of the equation or graphs the minimum coefficient of variation is predicted from one fast scan, and the number and optimum arrangement of additional counting periods to reduce variation to a desired limit may be obtained. The calculated coefficient is the maximum which may be attributed to the counting statistic but does not include experimental deviations.

Carbonate Rock Pore Size Distribution Determination through Iowa Pore Index Testing, MLR-15-01, 2015

The Iowa Pore Index (IPI) measures the pore system of carbonate (limestone and dolomite) rocks using pressurized water to infiltrate the pore system. This technique provides quantitative results for the primary and capillary (secondary) pores in carbonate rocks. These results are used in conjunction with chemical and mineralogical test results to calculate a quality number, which is used as a predictor of aggregate performance in Portland cement concrete (PCC) leading to the durability classification of the aggregate. This study had two main objectives: to determine the effect different aggregate size has on IPI test results and to establish the precision of IPI test and test apparatus. It was found that smaller aggregate size fractions could be correlated to the standard 1/2”-3/4” size sample. Generally, a particle size decrease was accompanied by a slight decrease in IPI values. The IPI testing also showed fairly good agreement of the secondary pore index number between the 1/2”-3/4”and the 3/8”-1/2” fraction. The #4-3/8” showed a greater difference of the secondary number from the 1/2”-3/4” fraction. The precision of the IPI test was established as a standard deviation (Sr) of 2.85 (Primary) and 0.87 (Secondary) with a repeatability limit (%r) of 8.5% and 14.9% for the primary and secondary values, respectively.

Iowa Fen Rapid Assessment Method for Wetlands v. 1 Quantitative Rating, 2016

Rapid assessment methods are valuable tools for collecting information about the quality and status of natural systems. However, they are not a substitute for detailed surveys of those systems. Users of this method should consider that the method may under-score or over-score the site that’s assessed, especially when the site is not a typical fen (i.e. a sedge meadow could score lower than fens, but in-fact be a relatively high quality sedge meadow). This assessment can be used throughout most of the spring, summer and fall period, however the ideal “index period” would be from late May through early October when native plant communities, as well as invasive species, are most apparent.

Quantitative Guidelines for Thin Maintenance Surfaces, TR-435, 2003

What follows are the refined guidelines from the Thin Maintenance Surface: Phase II Report. For that report, test sections were created and monitored along with some existing test sections. From the monitoring and evaluation of these test sections, literature reviews, and the experience and knowledge of the authors, the following guidelines were created. More information about thin maintenance surfaces and their uses can be found in the above-mentioned report.