31 resultados para elastic-plastic material

em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States


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Report to Margaret Thompson, Chief Clerk, about Recycled Content Plastic Bag and Soy Inks.

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Report to Margaret Thompson, Chief Clerk, about Recycled Content Plastic Bag and Soy Inks.

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Report to Margaret Thompson, Chief Clerk, about Recycled Content Plastic Bag and Soy Inks.

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The chemistry of today’s concrete mixture designs is complicated by many variables, including multiple sources of aggregate and cements and a plethora of sometimes incompatible mineral and chemical admixtures. Concrete paving has undergone significant changes in recent years as new materials have been introduced into concrete mixtures. Supplementary cementitious materials such as fly ash and ground granulated blast furnace slag are now regularly used. In addition, many new admixtures that were not even available a few years ago now have widespread usage. Adding to the complexity are construction variables such as weather, mix delivery times, finishing practices, and pavement opening schedules. Mixture materials, mix design, and pavement construction are not isolated steps in the concrete paving process. Each affects and is affected by the other in ways that determine overall pavement quality and long-term performance. Equipment and procedures commonly used to test concrete materials and concrete pavements have not changed in decades, leaving serious gaps in our ability to understand and control the factors that determine concrete durability. The concrete paving community needs tests that will adequately characterize the materials, predict interactions, and monitor the properties of the concrete.

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Report to Margaret Thomson, Chief Clerk, about Recycled Content Plastic Bag and Soy Inks.

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Severe environmental conditions, coupled with the routine use of deicing chemicals and increasing traffic volume, tend to place extreme demands on portland cement concrete (PCC) pavements. In most instances, engineers have been able to specify and build PCC pavements that met these challenges. However, there have also been reports of premature deterioration that could not be specifically attributed to a single cause. Modern concrete mixtures have evolved to become very complex chemical systems. The complexity can be attributed to both the number of ingredients used in any given mixture and the various types and sources of the ingredients supplied to any given project. Local environmental conditions can also influence the outcome of paving projects. This research project investigated important variables that impact the homogeneity and rheology of concrete mixtures. The project consisted of a field study and a laboratory study. The field study collected information from six different projects in Iowa. The information that was collected during the field study documented cementitious material properties, plastic concrete properties, and hardened concrete properties. The laboratory study was used to develop baseline mixture variability information for the field study. It also investigated plastic concrete properties using various new devices to evaluate rheology and mixing efficiency. In addition, the lab study evaluated a strategy for the optimization of mortar and concrete mixtures containing supplementary cementitious materials. The results of the field studies indicated that the quality management concrete (QMC) mixtures being placed in the state generally exhibited good uniformity and good to excellent workability. Hardened concrete properties (compressive strength and hardened air content) were also satisfactory. The uniformity of the raw cementitious materials that were used on the projects could not be monitored as closely as was desired by the investigators; however, the information that was gathered indicated that the bulk chemical composition of most materials streams was reasonably uniform. Specific minerals phases in the cementitious materials were less uniform than the bulk chemical composition. The results of the laboratory study indicated that ternary mixtures show significant promise for improving the performance of concrete mixtures. The lab study also verified the results from prior projects that have indicated that bassanite is typically the major sulfate phase that is present in Iowa cements. This causes the cements to exhibit premature stiffening problems (false set) in laboratory testing. Fly ash helps to reduce the impact of premature stiffening because it behaves like a low-range water reducer in most instances. The premature stiffening problem can also be alleviated by increasing the water–cement ratio of the mixture and providing a remix cycle for the mixture.

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Report to Margaret Thomson, Chief Clerk, about Recycled Content Plastic Bag and Soy Inks.

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As required in Iowa Code section 307.21, this is a summary of purchasing activity for soy-based inks and recycled content trash bags. The figures are for fiscal year 2007.

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As required in Iowa Code section 307.21, the Iowa Department of Transportation submits the following summary of purchasing activity for soy based inks and recycled trash bags. The figures are for Fiscal Year 2008.

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As required by Iowa Code section 307.21, figures for Fiscal Year 2009 for purchasing activity for soy-based inks and recycled content trash bags.

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As required by Iowa Code section 37.21, the following is a summary of purchasing activities for soy-based inks and recycled content plastic trash bags. The figures are for Fiscal Year 2010. The department currently has no equipment which will operate with soy ink. Iowa Code section 8A.315 required that a minimum of 50 percent of garbage can liner purchases shall be recycled content plastic garbage can liners. The department purchased $51.478.04 worth of recycled content plastic garbage can liners. The represents 93.9 percent of garbage can liners purchased.

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Benjamin F. Shambaugh edited and compiled documents and publications for this book on the history of Iowa. This volume 1 includes documentary material from the Louisiana Purchase, the Territories of the Northwest, Wisconsin and Iowa; the Convention of 1857;the Iowa Constitution of 1846 and the Ratification of Constitutional Amendments.

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Benjamin F. Shambaugh edited and compiled documents and publications for this book on the history of Iowa. This volume 2 is concerned with the history of local political organizations and documents illustrative of the development of local government in the Territory of the Northwest from 1787 to 1800, in the Territory of Indiana from 1800 to 1805 and in the Territory of Michigan from 1805 to September 6, 1834.

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Benjamin F. Shambaugh edited and compiled documents and publications for this book on the history of Iowa. This volume 3 is a continuation of volume 2 which is concerned with the history of local political organization from 1787 to 1834. Documents are illustrative of the development of local government in Iowa from the establishment of the Territory of Wisconsin in 1836 to the revision of the statutes of Iowa in 1842-43. It includes documentary material from the Louisiana Purchase, the Territories of the Northwest, Wisconsin and Iowa; the Convention of 1857; the Iowa Constitution of 1846 and the Ratification of Constitutional Amendments.

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As required by Iowa Code section 307.21, the following report was submitted related to the purchase of soy based inks and recycled content trash bags.