Audit report on the Shelby County Area Solid Waste Agency for the year ended June 30, 2014

Audit report on the Shelby County Area Solid Waste Agency for the year ended June 30, 2014

Audit report on the Pocahontas County Solid Waste Commission for the year ended June 30, 2014

Audit report on the Pocahontas County Solid Waste Commission for the year ended June 30, 2014

Audit report on the Crawford County Area Solid Waste Agency Commission for the year ended June 30, 2014

Audit report on the Crawford County Area Solid Waste Agency Commission for the year ended June 30, 2014

Audit report on the Water and Waste Disposal Systems for Rural Communities program for the City of Lone Rock, Iowa for the year ended June 30, 2014

Audit report on the Water and Waste Disposal Systems for Rural Communities program for the City of Lone Rock, Iowa for the year ended June 30, 2014

Audit report on the North Central Iowa Regional Solid Waste Agency for the year ended June 30, 2014

Audit report on the North Central Iowa Regional Solid Waste Agency for the year ended June 30, 2014

Audit report on the Wayne-Ringgold-Decatur County Solid Waste Management Commission for the year ended June 30, 2014

Audit report on the Wayne-Ringgold-Decatur County Solid Waste Management Commission for the year ended June 30, 2014

Audit report on the Waste Authority of Jackson County for the year ended June 30, 2014

Audit report on the Waste Authority of Jackson County for the year ended June 30, 2014

Audit report on the Butler County Solid Waste Commission for the year ended June 30, 2014

Audit report on the Butler County Solid Waste Commission for the year ended June 30, 2014

Wood waste processing in Iowa, 1996

The objective of this report is to gain a better understanding of the wood waste market in Iowa through surveying the processors of wood waste. A survey was sent out by the Iowa Department of Natural Resources Management Assistance Division to 147 public waste management organizations and private businesses with a questionnaire which asked for details of any wood waste processing operation.

Audit report on the Delaware County Solid Waste Disposal Commission for the year ended June 30, 2014

Audit report on the Delaware County Solid Waste Disposal Commission for the year ended June 30, 2014

Effects of Cement on Moisture Migration in Concrete, Phase A, Laboratory Study of Moisture Migration in Hardened Cement Paste, HR-141, 1972

The Columbus Laboratories of Battelle Memorial Institute is currently conducting a study of the effect of cement on moisture migration in concrete as related to the problem of D-cracking of portland cement concrete pavements. The study began on December 31, 1970, and is planned as a 3-year program. The work plan, approved by the policy committee of the members of the Iowa, Kansas, and Missouri highway departments and the Federal Highway Administration, is composed of four parts. The first phase (A) of the investigation concerned the movement of moisture into and from hardened cement pastes and the dimensional changes accompanying the moisture changes. Small slab specimens of hardened neat cement pastes were prepared from 32 different cements which were prepared at the same water/cement ratio and hydrated to the same maturity factor.

Audit report on the Great River Regional Waste Authority for the year ended June 30, 2014

Audit report on the Great River Regional Waste Authority for the year ended June 30, 2014

A Laboratory Investigation of An Accelerated Polishing Method for Determining the Skid Resistance Potential of Aggregates, MLR-76-02 and R-264, 1976

An initial feasibility study indicated that the "Purdue Accelerated Polishing Method" gave repeatable results when testing the skid resistance of laboratory specimens. The results also showed a rough correlation with the field performance of the same aggregate sources. The research was then expanded to include all available asphalt aggregates. The results of the expanded study indicated that the method is not presently capable of developing and measuring the full skid potential of the various aggregate sources. Further research in the area of polishing times and/or pressures is needed.

Laboratory Study of the Leachate from Crushed Portland Cement Concrete Base Material, MLR-96-04, 1999

Since the 1980s, the Iowa Department of Transportation has increased its use of recycled Portland Cement Concrete (PCC) as drainable base material below some new pavements. Water flowing out of the longitudinal drains on projects having recycled PCC drainable bases was found to have a high pH value. The high pH water impedes vegetation growth and becomes a contributing factor to soil erosion at the drain outlet. In addition, the high pH water contributes to the growth of crystalline deposits on the drain outlet wire mesh rodent guard and in some cases caused it to become completely blocked. This research determined which of three choices of recycled PCC drainable base material, gradation, and design would give the lowest pH value in the drain discharge water. The drainable base material having its fines separated out and placed as a 2-in. (5.1-mm) bottom layer, below the remaining coarse material, generally gave pH values around 11.2 while other designs tested gave pH values around 11.5.

Evaluation of Long-Term Field Performance of Cold In-Place Recycled Roads: Field and Laboratory Testing, TR-502, 2007

Cold in-place recycling (CIR) has become an attractive method for rehabilitating asphalt roads that have good subgrade support and are suffering distress related to non-structural aging and cracking of the pavement layer. Although CIR is widely used, its use could be expanded if its performance were more predictable. Transportation officials have observed roads that were recycled under similar circumstances perform very differently for no clear reason. Moreover, a rational mix design has not yet been developed, design assumptions regarding the structural support of the CIR layer remain empirical and conservative, and there is no clear understanding of the cause-effect relationships between the choices made during the design/construction process and the resulting performance. The objective of this project is to investigate these relationships, especially concerning the age of the recycled pavement, cumulative traffic volume, support conditions, aged engineering properties of the CIR materials, and road performance. Twenty-four CIR asphalt roads constructed in Iowa from 1986 to 2004 were studied: 18 were selected from a sample of roads studied in a previous research project (HR-392), and 6 were selected from newer CIR projects constructed after 1999. This report describes the results of comprehensive field and laboratory testing for these CIR asphalt roads. The results indicate that the modulus of the CIR layer and the air voids of the CIR asphalt binder were the most important factors affecting CIR pavement performance for high-traffic roads. For low-traffic roads, the wet indirect tensile strength significantly affected pavement performance. The results of this research can help identify changes that should be made with regard to design, material selection, and construction in order to improve the performance and cost-effectiveness of future recycled roads.