Sustainable Concrete Pavements: A Manual of Practice, January 2012

Sustainable Concrete Pavements: A Manual of Practice is a product of the National Concrete Pavement Technology Center at Iowa State University’s Institute for Transportation, with funding from the Federal Highway Administration (DTFH61-06-H-00011, Work Plan 23). Developed as a more detailed follow-up to a 2009 briefing document, Building Sustainable Pavement with Concrete, this guide provides a clear, concise, and cohesive discussion of pavement sustainability concepts and of recommended practices for maximizing the sustainability of concrete pavements. The intended audience includes decision makers and practitioners in both owner-agencies and supply, manufacturing, consulting, and contractor businesses. Readers will find individual chapters with the most recent technical information and best practices related to concrete pavement design, materials, construction, use/operations, renewal, and recycling. In addition, they will find chapters addressing issues specific to pavement sustainability in the urban environment and to the evaluation of pavement sustainability. Development of this guide satisfies a critical need identified in the Sustainability Track (Track 12) of the Long-Term Plan for Concrete Pavement Research and Technology (CP Road Map). The CP Road Map is a national research plan jointly developed by the concrete pavement stakeholder community, including Federal Highway Administration, academic institutions, state departments of transportation, and concrete pavement–related industries. It outlines 12 tracks of priority research needs related to concrete pavements. CP Road Map publications and other operations support services are provided by the National Concrete Pavement Technology Center at Iowa State University. For details about the CP Road Map, see www.cproadmap. org/index.cfm.

Evaluation of Microcracking and Chemical Deterioration in Concrete Pavements Final Report, October 31, 1995

The major objective of this research project was to investigate the chemistry and morphology of portland cement concrete pavements in Iowa. The integrity of the various pavements was evaluated qualitatively, based on the presence or absence of microcracks, the presence or absence of sulfate minerals, and the presence or absence of alkali-silica gel(s). Major equipment delays and subsequent equipment replacements resulted in significant delays over the course of this research project. However, all these details were resolved and the equipment is currently in place and fully operational. The equipment that was purchased for this project included: ( I ) a LECO VP 50, 12-inch diameter, variable speed grinder/polisher: (2) a Hitachi S-2460N variable pressure scanning electron microscope; and (3) a OXFORD Instruments Link ISIS microanalysis system with a GEM (high-purity germanium) X-ray detector. This study has indicated that many of the concrete pavements contained evidence of multiple deterioration mechanisms: and hence, the identification of a single reason for the distress that was observed in any given pavement typically had to be based on opinion rather than empirical evidence.

Evauation of Recycled Asphalt Concrete Pavements: Final Report for Kossuth County, Iowa, HR-1888, February 1980

After some success with a small asphalt pavement recycling project in 1975, Kossuth County, Iowa programmed a much larger undertaking during the 1976 construction season. The work performed in 1975 indicated that a quality product could be produced with some modifications to conventional equipment. As anticipated , the major problem encountered was the excessive air pollution created during the heating and mixing process. As part of its 1976 road program, Kossuth County developed plans for recycling sixteen miles of existing asphalt pavements using the "hot mix" recycling process. One project, ten miles in length, was selected by the Federal Highway Authority as part of "Demonstration Project No. 39, Recycling Asphalt Pavements." The FHWA provided a $29,500 grant t o the project to be used for project testing and evaluation. Cooperation and input into the work proposed for 1976 was received from many sources. The people and organizations contributing were the Federal Highway Authority, the Iowa Department of Environmental Quality, the Federal Environmental Protection Agency, several contractors, and personnel from the Kossuth County Engineer's Office.

Concrete Pavement Mixture Design and Analysis (MDA) Guide Specification for Highway Concrete Pavements: Commentary, TPF-5(205), 2012

This guide specification and commentary for concrete pavements presents current state-of-the art thinking with respect to materials and mixture selection, proportioning, and acceptance. This document takes into account the different environments, practices, and materials in use across the United States and allows optional inputs for local application. The following concrete pavement types are considered: jointed plain concrete pavement, the most commonly used pavement type and may be doweled or non-doweled at transverse joints; and continuously reinforced concrete pavement, typically constructed without any transverse joints, typically used for locations with high truck traffic loads and/or poor support conditions.

Concrete Pavement Mixture Design and Analysis (MDA) Guide Specification for Highway Concrete Pavements, TPF-5(205), 2012

A guide specification and commentary have been prepared that lay out current state-of-the art thinking with respect to materials and mixture selection, proportioning, and acceptance. These documents take into account the different environments, practices, and materials in use across the US and allow optional inputs for local application.

Investigation of Deterioration of Joints in Concrete Pavements , TPF-5(224), 2012

Premature deterioration of concrete at the joints in concrete pavements and parking lots has been reported across the northern states. The distress is first observed as shadowing when microcracking near the joints traps water, later exhibiting as significant loss of material. Not all roadways are distressed, but the problem is common enough to warrant attention. The aim of the work being conducted under this and parallel contracts was to improve understanding of the mechanisms behind premature joint deterioration and, based on this understanding, develop training materials and guidance documents to help practitioners reduce the risk of further distress and provide guidelines for repair techniques. While work is still needed to understand all of the details of the mechanisms behind premature deterioration and prevention of further distress, the work in this report has contributed to advancing the state of knowledge.

Non-Destructive Evaluation of Iowa Pavements Phase 2: Development of a Fully Automated Software System for Rapid Analysis/Processing of the Falling Weight Deflectometer Data, 2009

The Office of Special Investigations at Iowa Department of Transportation (DOT) collects FWD data on regular basis to evaluate pavement structural conditions. The primary objective of this study was to develop a fully-automated software system for rapid processing of the FWD data along with a user manual. The software system automatically reads the FWD raw data collected by the JILS-20 type FWD machine that Iowa DOT owns, processes and analyzes the collected data with the rapid prediction algorithms developed during the phase I study. This system smoothly integrates the FWD data analysis algorithms and the computer program being used to collect the pavement deflection data. This system can be used to assess pavement condition, estimate remaining pavement life, and eventually help assess pavement rehabilitation strategies by the Iowa DOT pavement management team. This report describes the developed software in detail and can also be used as a user-manual for conducting simulation studies and detailed analyses. *********************** Large File ***********************

Response of Iowa Pavements to a Tracked Agricultural Vehicle, HR-1075, Phase II, 2000

The overall objective of the work summarized in this report and in the interim report was to study the effects of targeted implement-of-husbandry loads. This report is to complement phase I of this work, which was summarized in the interim report, entitled Response of Iowa Pavements to Heavy Agricultural Loads (December 1999). The response of newly constructed Portland cement concrete (PCC) and asphalt cement concrete (ACC) pavements under semitruck, single-axle single-tire grain wagon, single-axle dual-tire grain wagon, tandem and tridem tank wagons were summarized in the interim report. Phase II of this project, presented herein, was to complete the study in terms of how tracked agricultural vehicles relate to the reference 20,000-pound single-axle semi-truck. In this report the response of these two pavements under a tracked grain wagon is documented.

Response of Iowa Pavements to Heavy Agricultural Loads, HR-1075, 1999

Iowa's county road system includes several thousands of miles of paved roads which consist of Portland cement concrete (PCC) surfaces, asphalt cement concrete (ACC) surfaces, and combinations of thin surface treatments such as seal coats and slurries. These pavements are relatively thin pavements when compared to the state road system and therefore are more susceptible to damage from heavy loads for which they were not designed. As the size of the average farm in Iowa has increased, so have the size and weights of implements of husbandry. These implements typically have fewer axles than a truck hauling the same weight would be required to have; in other words, some farm implements have significantly higher axle weights than would be legal for semi-trailers. Since stresses induced in pavements are related to a vehicle's axle weight, concerns have been raised among county and state engineers regarding the possible damage to roadway surfaces that could result from some of these large implements of husbandry. Implements of husbandry on Iowa's highway system have traditionally not been required to comply with posted weight embargo on bridges or with regulations regarding axle-weight limitations on roadways. In 1999, with House File 651, the Iowa General Assembly initiated a phased program of weight restrictions for implements of husbandry. To help county and state engineers and the Iowa legislature understand the effects of implements of husbandry on Iowa's county roads, the following study was conducted. The study investigated the effects of variously configured grain carts, tank wagons, and fence-line feeders on Iowa's roadways, as well as the possible mitigating effects of flotation tires and tracks on the transfer of axle weights to the roadway. The study was accomplished by conducting limited experimental and analytical research under static loading conditions

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.

Low Modulus Hot Pour Joint Sealant for ACC Pavements, HR-534, 1990

Over the years, the Iowa Department of Transportation has established an outstanding network of connector highways across the state of Iowa. Construction and paving of these primary roadways has essentially been completed. Unfortunately, many of these primary highway pavements are reaching their design life and are in need of rehabilitation. The emphasis, therefore, has shifted from the construction of new highways to the maintenance and rehabilitation of existing highways. The Iowa DOT in recent years has become more concerned with preventing the ingress of surface water into the pavement structure. Crack sealing is receiving greater emphasis. Specifications have been modified to require improved low modulus crack and joint sealing materials.

An Evaluation of the Roto-Mill Profiler on Concrete Pavements in Iowa, MLR-76-1, 1976

A new machine, the ROTO-MILL Profiler, became available in early 1976. This machine, manufactured by CMI Corporation of Oklahoma City, Oklahoma provides pavement surface Scarification at a much higher production rate than was previously possible. Iowa had the opportunity to observe and evaluate this machine on two separate sections of primary portland cement concrete pavement in October, 1976. The marked improvement in the profile index and the skid resistance indicates this machine may be considered a viable method for improving rideability and skid resistance of a roadway that is otherwise reasonably sound.

Determination of the Optimum Base Characteristics for Pavements, TR-482, 2004

In recent years, it has become apparent that the design and maintenance of pavement drainage extends the service life of pavements. Most pavement structures now incorporate subsurface layers. Part of the function of these subsurface layers is to drain away excess water, which can be extremely deleterious to the life of the pavement. To assure the effectiveness of such drainage layers after they have been spread and compacted, simple, rapid, in-situ permeability and stability testing and end-result specification are needed. This report includes conclusions and recommendations related to four main study objectives: (1) Determine the optimal range for in-place stability and in-place permeability based on Iowa aggregate sources; (2) Evaluate the feasibility of an air permeameter for determining the permeability of open and well-graded drainage layers in situ; (3) Develop reliable end-result quality control/quality assurance specifications for stability and permeability; and (4) Refine aggregate placement and construction methods to optimize uniformity.

Dynamic Deflections for Determining Structural Rating of Flexible Pavements, HR-178, 1979

The Road Rater is a dynamic deflection measuring apparatus for flexible base pavements. The Road Rater replaces the Benkelman Beam which was last used by the Iowa DOT in 1977. Road Rater test results correlate reasonably well (correlation coefficient = 0.83) with Benkelman Beam test data. The basic differences between the Road Rater and Benkelman Beam are as follows: 1. The Benkelman Beam uses a static 18,000 lb. load while the Road Rater uses a dynamic 800 to 2,000 lb. loading. 2. The Road Rater tests much faster and more economically than the Benkelman Beam. 3. The Road Rater better simulates a moving truck than the Benkelman Beam. The basic operating principle of the Road Rater is to impart a dynamic loading and measure the resultant movement of the pavement with velocity sensors. This data, when properly adjusted for temperature by use of a nomograph included in this report, can be used to determine pavement life expectancy and estimate overlay thickness required. Road Rater testing will be conducted in the spring, when pavements are in their weakest condition, until seasonal correction factors can be developed. The Road Rater does not have sufficient ram weight to effectively evaluate load carrying capacity of rigid pavements. All rigid pavements react similarly to Road Rater testing and generally deflect from 0.65 to 1.30 mils. Research will be contined to evaluate rigid pavements with the Road Rater, however. The Road Rater has proven to be a reliable, troublefree pavement evaluation machine. The deflection apparatus was originally front-mounted,but was rear-mounted during the winter of 1977-78. Since that time, van handling has greatly improved, and front suspension parts are no longer overstressed due to improper weight distribution.

Structural Analysis and Overlay Design of Pavements Using the Road Rater, MLR-84-3, 1986

In recent years the Iowa DOT has shifted emphasis from the construction of new roads to the maintenance and preservation of existing highways. A need has developed for analyzing pavements structurally to select the correct rehabilitation strategy and to properly design a pavement overlay if necessary. This need has been fulfilled by Road Rater testing which has been used successfully on all types of pavements to evaluate pavement and subgrade conditions and to design asphaltic concrete overlays. The Iowa Road Rater Design Method has been simplified so that it may be easily understood and used by the widely diverse groups of individuals which may be involved in pavement restoration and management. Road Rater analysis techniques have worked well to date and have been verified by pavement coring, soils sampling and testing, and pavement removal by block sampling. Void detection testing has also been performed experimentally in Iowa, and results indicate that the Road Rater can be used to locate pavement voids and that Road Rater analysis techniques are reasonably accurate. The success of Road Rater research and development has made deflection test data one of the most important pavement management inputs.