Void Ratio and Shear Strength of Two Compacted Crushed Stones, Progress Report, HR-99

Triaxial compression tests of two crushed limestones of differing highway service records indicate a fundamental difference in their shear strength -- void ratio relationship. Analyses were based on stress parameters at minimum sample volume, i.e., before there was significant sample dilation due to shear. The better service record sample compacted to higher density, and had a high effective angle of internal friction and zero effective cohesion. The other sample compacted to lower density and had a lower friction angle, but gained significant stability from effective cohesion. Repeated loading-unloading cycles reduced the cohesion, apparently due to modification of the sample structure. Extrapolations of the results to zero void ratio agree with sliding friction data reported on calcite, or with triaxial parameters reported on carbonate rocks.

Durability of Concrete as Affected by Variations in Air and W/C Ratio, R-258, 1975

Many times during the past four years we have seen ranges in the durability factor for a single coarse aggregate source that were too great to be explained by variations in the coarse aggregate alone. The durability test (ASTM C 666 Method B) as presently used is a test of the concrete system rather than that of a particular coarse aggregate. An informal study of current durability factor data indicates that w/c ratio and/or percentage of air may be critical to beam growth and durability factor. The purpose of this project, R-258, is to determine the extent w/c ratio and air content variations have on beam growth and durability factor when other factors including coarse aggregate gradation are held constant.

Health consultation : Exposure to fluff material from the Shine Brothers and noise concerns -- Spencer, Iowa (2011)

This letter has been prepared as a consultation to determine some potential health concerns raised by a resident of Spencer from exposure to wire shredder fluff material emitted by Shine Brothers metal salvaging facility in Spencer, Iowa on July 10, 2011 and, a concern regarding the health impacts from the level of noise measured by a resident near the metal salvaging facility.

Letter health consultation : Exposure to benzene from Equistar pyrolysis gasoline tank, Clinton, Iowa (2008)

The Iowa Department of Public Health (IDPH) has been asked by several citizens of Clinton, Iowa to evaluate potential health effects from exposure to benzene from an above ground tank located near a residential area. The above ground tank is managed by Equistar Chemicals, LP (Equistar) and is use to store pyrolysis gasoline prior to off-loading onto barges. The IDPH in cooperation with the Agency for Toxic Substances and Disease Registry (ATSDR) prepared this health consultation to review the air quality monitoring provided by Equistar and provide an evaluation of the health effects from exposure to benzene at the levels detected in ambient air near the tank. The information in this health consultation was current at the time of writing. Data that emerges later could alter this document’s conclusions and recommendations.

Lessons Learned: Acute Mercury Poisoning From A Residential Work/Hobby Exposure In Iowa, 2014

This document is about the different ways Mercury can poison a person and the exposure in Iowa.