Robert Otto Rasmussen

VALIDATION OF HIPERPAV FOR PREDICTION OF EARLY-AGE JOINTED CONCRETE PAVEMENT BEHAVIOR

HIPERPAV is a computer program that was developed to predict the time growth of early-age portland cement concrete strength and stresses in jointed concrete pavements for the prediction of cracking. Each individual environmental, construction, design, and mix design input that influences early-age pavement behavior can be adjusted to find the optimum paving solution. A design that minimizes stresses and maximizes concrete strength will increase the potential for an extended service life. FHWA, aware of the benefits that HIPERPAV can provide in the field, provided funding for experimental validation. The results of this validation are presented. The experimental field instrumentation efforts are described and the analyses performed are discussed. The end result of validating HIPERPAV is increased confidence in the accurate prediction of early-age pavement behavior.

IDENTIFICATION OF PAVEMENT FAILURE MECHANISMS AT FHWA ACCELERATED LOADING FACILITY ULTRATHIN WHITETOPPING PROJECT

In 1998 eight test lanes of ultrathin whitetopping (UTW) were constructed over existing hot-mix asphalt (HMA) pavements at FHWA’s Accelerated Loading Facility (ALF) located at the Turner-Fairbank Highway Research Center in McLean, Virginia. Various combinations of thicknesses, joint spacings, fiber reinforcement, and types of HMA base were used. In spring 2000 the loading experiment of these pavements was completed, and the analysis of behavior and performance was begun. A summary of some of the pavement distresses observed at the ALF is presented, and hypothesized failure mechanisms are identified, providing an addition to the state of the knowledge with respect to the actual life cycle of UTW pavements.

Strength Prediction by Using Maturity for Portland Cement Concrete Pavement Construction at Airfields

A recent demonstration of a noncomplex solution for monitoring concrete strengths in real time used concrete maturity technology. During a recent airfield concrete pavement construction project in Des Moines, Iowa, several commercially available maturity measurement devices were evaluated along with an innovative strength assessment and prediction system, Total Environmental Management for Paving. This field evaluation demonstrated that current maturity technology could be used to assess the strength of a concrete airfield pavement successfully in real time. Furthermore, the adoption of maturity-based technologies can expedite airfield repair and construction and can expand the knowledge of concrete pavement as it is placed.

Nonwoven Geotextile Interlayers in Concrete Pavements

Pavement engineers are constantly seeking proven innovative concepts with the potential to improve pavement performance while reducing costs. An example of such a concept is the use of a nonwoven geotextile as an alternative to hot-mix asphalt between cementitious layers. Proven by German engineers to be effective, this concept is not common or widespread in the United States. However, as part of a recent effort to demonstrate the use of nonwoven geotextile interlayers as concrete pavement interlayers, initial recommendations for materials specifications and better construction practices were developed. Implementation of a nonwoven geotextile interlayer was successful in two recent field trials in Missouri and Oklahoma. The material proved to be cost-effective, required minimal training and equipment during construction, and could be placed rapidly. As a result, nonwoven geotextiles have the potential to be a viable alternative to more conventional materials as an interlayer in U.S. pavements.

Constructing High-Performance Concrete Pavements with FHWA HIPERPAV Systems Analysis Software

HIPERPAV (high-performance paving) is a concrete paving software product developed jointly by FHWA and The Transtec Group, Inc., and is intended to serve as a tool in the proper selection and control of the factors affecting concrete pavement behavior at early ages. Adequate selection and control of these factors will ensure good performance throughout the design life of the pavement. Praised by industry, agencies, and academia, HIPERPAV is the first software tool of its kind to provide real control over concrete pavement design and construction. With HIPERPAV, materials, pavement design, and construction operations can now successfully be integrated into one easy-to-use Windows based software package. This integration captures all aspects of a concrete pavement construction project and provides a real systems approach to analysis of the first 72 h after construction. With a true systems approach, the development of stresses and strength in concrete pavement can be assessed during these critical first 72 h to maximize quality, increase long-term performance, boost productivity, and optimize pavement options. A brief history of the development, validation, and implementation of the HIPERPAV software to date is presented.

Quiet concrete pavement surfaces

For the last 5 years, a comprehensive evaluation has been conducted on hundreds of concrete pavement surfaces throughout the US, Canada, andEurope. These data have been synthesized in a manner that allows the highway industry to make important decisions about how best to design and construct concrete pavements to reduce tire‐pavement noise levels without compromising other important aspects such as durability, safety, and cost. While a significant amount of variability is present in the data, clear trends have been identified. Some surfaces, such as diamond grinding, appear to be among the best alternatives available today for reducing tire‐pavement noise. Meanwhile, recent trials of more unconventional surfaces have yielded mixed results. In the end, the techniques for concrete pavement surfacing today include a vast array of choices. The selection of the best surface for the particular job can now be made more confidently given this improved understanding of the potential impacts due to tire‐pavement noise.

Early-Age Behavior of Concrete Overlays on Continuously Reinforced Concrete Pavements

Delamination is the primary mode of distress in most bonded concrete overlay (BCO) projects. The objective of the present study was to develop and calibrate a mechanistic delamination model to properly predict the early-age behavior of concrete overlays bonded to continuously reinforced concrete pavements (CRCPs). An experimental BCO on a CRCP section was constructed to monitor its behavior, and the field data were used to calibrate the mechanistic models. Two- and three-dimensional finite element models of the BCO on CRCPs were developed and calibrated. The results from the numerical analysis matched the experimental results well. Equations to predict the interfacial stresses at the corner of the composite structure by use of the two-dimensional finite element model were also developed. A sensitivity analysis was performed to investigate the effects of overlay and CRCP parameters, such as elastic modulus, thickness, coefficient of thermal expansion, and percent reinforcement, on the shear and interfacial normal stresses. This mechanistic model has been incorporated into the HIPERBOND (High-Performance Bonded Concrete Overlays) software developed for FHWA.