Measuring Pavement Profile at the Slip-Form Paver, May 2005

Pavement profile or smoothness has been identified nationally as a good measure of highway user satisfaction. This has led highway engineers to measure profiles of both operating and new highways. Operational highway profiles are often measured with high-speed inertial profilers. New highway profiles are usually measured with profilographs in order to establish incentives or disincentives for pavement construction. In most cases, these two processes do not measure the same value from the “cradle to grave” life of pavements. In an attempt to correct the inconsistency between measuring techniques, lightweight profilers intended to produce values to be used for construction acceptance are being made that measure the same profile as high-speed inertial profilers. Currently, two profiler systems have been identified that can measure pavement profile during construction. This research has produced a field evaluation of the two systems. The profilers evaluated in this study are able to detect roughness in the final profile, including localized roughness and roughness at joints. Dowel basket ripple is a significant source of pavement surface roughness. The profilers evaluated in this study are able to detect dowel basket ripple with enough clarity to warn the paving crew. String-line disturbances degrade smoothness. The profilers evaluated in this study are able to detect some string-line disturbances during paving operations. The profilers evaluated in this study are not currently able to produce the same absolute International Roughness Index (IRI) values on the plastic concrete that can be measured by inertial profilers on the hardened concrete. Construction application guidelines are provided.

Stringless Portland Cement Concrete Paving, February 2004

This report describes results from a study evaluating the use of stringless paving using a combination of global positioning and laser technologies. CMI and Geologic Computer Systems developed this technology and successfully implemented it on construction earthmoving and grading projects. Concrete paving is a new area for considering this technology. Fred Carlson Co. agreed to test the stringless paving technology on two challenging concrete paving projects located in Washington County, Iowa. The evaluation was conducted on two paving projects in Washington County, Iowa, during the summer of 2003. The research team from Iowa State University monitored the guidance and elevation conformance to the original design. They employed a combination of physical depth checks, surface location and elevation surveys, concrete yield checks, and physical survey of the control stakes and string line elevations. A final check on profile of the pavement surface was accomplished by the use of the Iowa Department of Transportation Light Weight Surface Analyzer (LISA). Due to the speed of paving and the rapid changes in terrain, the laser technology was abandoned for this project. Total control of the guidance and elevation controls on the slip-form paver were moved from string line to global positioning systems (GPS). The evaluation was a success, and the results indicate that GPS control is feasible and approaching the desired goals of guidance and profile control with the use of three dimensional design models. Further enhancements are needed in the physical features of the slipform paver oil system controls and in the computer program for controlling elevation.

Recidivism of State FY96 Prison Releases in Iowa, May 2001

Expanding on research first presented in the Iowa Board of Parole FY99 Annual Report, this report presents recidivism data on offenders released from Iowa prisons during State FY1996 (July 1, 1995 – June 30, 1996). The figures presented here differ from those included in last year’s report due to four changes in the study. First, this year’s research includes data on those released from work release facilities, who were inadvertently omitted last year. In addition, the current figures include an additional year of tracking, as a second round of “rapsheets” was obtained to detect recidivism occurring within the last year.2 Also enhancing this year’s report is the availability of national recidivism data through the Interstate Identification Index (III). Further, while last year’s data looked only at the first new offense following release, this year’s study examines the most serious new conviction, resulting in higher felony recidivism rates. One note of caution should be voiced concerning the use of out-of-state records. A review of these records suggests very incomplete disposition reporting in III from some other states. In examining these records, it was not unusual to find a string of serious arrests with no dispositions noted. It was tempting in these situations to conclude that there must have been a conviction at some point, but we have resisted that urge when presenting figures on new convictions. This report is not intended to be an all-encompassing review of recidivism. Rather, it is meant to provide an illustration of the types of recidivism data available on prison releases in Iowa. Readers interested in other analyses of the data are urged to contact CJJP with suggestions and requests.

Mulch Iowa: A Guide to the Benefits of Mulch and Why you should use mulch produced in Iowa, December 17, 2003

Mulch helps to recreate the organic layer and soil structure of a wooded environment, which benefits your trees and shrubs... • Helps maintain even soil temperature in the roots by keeping them cool in the summer and warm in the winter. • Promotes plant growth. • Controls weeds. • Conserves soil moisture, meaning you use less water. • Improves soil structure and quality over the root area. • Protects from mechanical damage (mowers, string trimmers, etc.) • Helps beautify the new planting.

Stringless Portland Cement Concrete Paving, TR-490, 2004

This report describes results from a study evaluating the use of stringless paving using a combination of global positioning and laser technologies. CMI and Geologic Computer Systems developed this technology and successfully implemented it on construction earthmoving and grading projects. Concrete paving is a new area for considering this technology. Fred Carlson Co. agreed to test the stringless paving technology on two challenging concrete paving projects located in Washington County, Iowa. The evaluation was conducted on two paving projects in Washington County, Iowa, during the summer of 2003. The research team from Iowa State University monitored the guidance and elevation conformance to the original design. They employed a combination of physical depth checks, surface location and elevation surveys, concrete yield checks, and physical survey of the control stakes and string line elevations. A final check on profile of the pavement surface was accomplished by the use of the Iowa Department of Transportation Light Weight Surface Analyzer (LISA). Due to the speed of paving and the rapid changes in terrain, the laser technology was abandoned for this project. Total control of the guidance and elevation controls on the slip-form paver were moved from string line to global positioning systems (GPS). The evaluation was a success, and the results indicate that GPS control is feasible and approaching the desired goals of guidance and profile control with the use of three dimensional design models. Further enhancements are needed in the physical features of the slipform paver oil system controls and in the computer program for controlling elevation.