A Notch-Strengthening Effect in Fresh-Water Ice

Tensile tests have been performed onnotched and unnotched cylindrical samples of randomlyoriented polycrystalline ice of controlled grain-size (between2.2 and 7.3mm) at a loading rate of lOOPaS-l and at a temperature of -10 0c. In the notched samples, the notch-root diameter was 80% of the base diameter. Anotch-strengthening effect was observed in the large-grained ice, with fracture stresses being up to 50% higher than that for unnotched samples of the same grain-size. This notch-strengthening effect diminished as grain-size decreased, disappearing at a grain-size of \u273 mm. The notch-strengthening effect is explained in terms of the triaxial stress constraint at the notch root. This triaxialconstraint results in a change in the controlling mechanismof fracture from crack propagation in the unnotchedsamples to crack initiation in the notched samples

Development of Chloride Reduction Training

The purpose of this project was to create a training program that could be used for Illinois Department of Transportation (IDOT) personnel who operated snow plows and spread road salt during winter storms. The training message was built around the three main goals of winter maintenance: safety, mobility, and environmental protection. The concept of winter maintenance operations being a system was introduced early in the training and stressed throughout. Another goal of the project was to develop a method or tool by which the effectiveness of the training could be measured. Achieving that goal requires the ability to compare quantities of salt used by IDOT (or some subset of IDOT, such as a maintenance garage) over winters before and after the training is provided. The method presented herein uses a storm severity index, summed over the whole winter season. This allows for comparison between two winters to be made by use of the index. Thus, as shown in the report, for the Moline maintenance district, the winter of 2012–13 can be compared with the winter of 2013–14. This comparison shows that the cumulative index for the 2012–13 winter was 13.20, while it was 26.88 for the 2013–14 winter. In other words the winter of 2013–14 was significantly worse than the winter that preceded it.Illinois Department of Transportation, R27-147Ope

Damaging effects of deicing chemicals on concrete materials,”

Abstract The damaging impact of various deicing chemicals and exposure conditions on concrete materials was investigated. Five deicing chemicals (sodium chloride, calcium chloride with and without a corrosion inhibitor, potassium acetate, and an agricultural product) were studied. Freezing-thawing (F-T) and wetting-drying (W-D) exposure conditions were considered. Mass loss, scaling, compressive strength, chemical penetration, and micro-structure of the paste and concrete subjected to these deicing chemicals and exposure conditions were evaluated. Results indicated that the various deicing chemicals penetrated at different rates into a given paste and concrete, resulting in different degrees of damage. Among the deicing chemicals tested, two calcium chloride solutions caused the most damage. Addition of a corrosion inhibitor into the calcium chloride solution delayed the onset of damage, but it did not reduce the ultimate damage. Chloride-related deicing chemicals often brought about leaching of calcium hydroxide, as well as chemical alterations in concrete. Potassium acetate caused minor scaling, associated with alkali carbonation of the surface layer of concrete. Although producing a considerable number of micro-pores on the surface of the samples, the agricultural deicing product resulted in the least chemical penetration and scaling damage of paste and concrete

Viscoelastic behavior of 80In15Pb5Ag and 50Sn50Pb alloys: Experiment and modeling

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