A Nondestructive Method for Determining the Thickness of Sound Concrete on Older Pavements, HR-250, 1983

The primary purpose of this project was to assess the potential of a nondestructive remote sensing system, specifically, ground penetrating subsurface interface radar, for identification and evaluation of D-cracking pavement failures. A secondary purpose was to evaluate the effectiveness of this technique for locating voids under pavements and determining the location of steel reinforcement. From the data collected and the analysis performed to date, the following conclusions can be made regarding the ground penetrating radar system used for this study: (1) steel reinforcement can be accurately located; (2) pavement thickness can be determined; (3) distressed areas in pavements can be located and broadly classified as to severity of deterioration; (4) voids under pavements can be located; and (5) higher resolution recording equipment is required to accurately determine both the thickness of sound pavement remaining over distressed areas and the depth of void areas under pavements.

Iowa Development of Rubblized Concrete Pavement Base - Mills County, HR-315, 1995

Iowa counties have tried to rehabilitate deteriorating portland cement concrete (PCC) pavements with standard overlays, placement of engineering fabric, rock, open graded bituminous mixes and cracking and seating. While these methods prolong the life of the road, the cracks in the old pavement have eventually reflected to the surface. One possible alternative for rehabilitating severely deteriorated roads and preventing reflective cracking is the rubblization process. The objective of this research project was to rehabilitate and evaluate a severely deteriorated PCC roadway using a rubblization process. A 3.0 km (1.9 mi) section of L63 in Mills County was selected for this research. The road was divided into 16 sections. A resonate frequency vibration pavement breaker was used to rubblize the existing pavement. The variables of rubblization, drainage, and ACC overlay depths of 75 mm (3 in.), 100 mm (4 in.), and 125 mm (5 in.) were evaluated. The research on rubblized concrete pavement bases support the following conclusions: (1) The rubblization process prevents reflective cracking; (2) Edge drains improved the structural rating of the rubblized roadway; (3) An ACC overlay of 125 mm (5 in.) on a rubblized base provided an excellent roadway regardless of soil and drainage conditions; (4) An ACC overlay of 75 mm (3 in.) on a rubblized base can provide a good roadway if the soil structure below the rubblized base is stable and well drained; and (5) The Road Rater structural ratings of the rubblized test sections for this project are comparable to the nonrubblized test sections.

Friday Facts, May 22, 2015, Vol. 250

Bureau of Nutrition and Health Promotion part of the Iowa Department of Public Health produces of weekly newsletter about the Iowa WIC Program for the State of Iowa citizen.

Iowa Development of Rubblized Concrete Pavement Base Mills County, Construction Report, HR-315, 1990

The concept of rubblizing existing concrete pavement prior to the placement of an asphaltic cement concrete overlay has been around for several years and, in fact, has been tried successfully in the states of New York, Michigan, and Ohio. With available construction and maintenance dollars usually not meeting the demands of the needed work, much of the necessary rehabilitation of existing Portland cement concrete pavements is not being completed when it would be most beneficial. Research project HR-315, "Iowa Development of Rubblized Concrete", has been undertaken to determine the effects of rubblized concrete pavement base as it affects the cracking pattern and longevity of the ACC overlay.