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Concrete pavement performance models are evaluated, calibrated, and validated using field data from databases like the Long-Term Pavement Program. Conceptually, performance model predictions should match field data considering a reliability of 50%; that is, there is a 50% probability that the predictions of a certain distress indicator are higher or lower than the field data. However, modern pavements are designed for higher levels of reliability (usually 90% to 95%). Local performance model evaluation for higher levels of reliability requires a high amount of field data that traditional databases lack. Pavement management system (PMS) databases can be a useful resource for high reliability model analysis because of the large amount of data collected locally and regularly. However, when selecting and filtering field databases (of any source), the effect of censored performance data due to rehabilitation, removal from service, or modification of pavement sections is usually ignored. This paper proposes an approach for the use of PMS databases accounting for censored performance data to evaluate the accuracy of performance models' high reliability predictions. The approach is exemplified using a PMS transverse joint faulting database. Results show that by addressing the "survival issue," i.e., accounting for the censored performance data, the resulting PMS-based reliability model improves the faulting model accuracy in matching the field data for high reliability levels. [ABSTRACT FROM AUTHOR]

This paper presents a new numerical procedure for the determination of the viscoelastic compliance properties of a matrix phase from a simple three-point bending test on a composite beam. The composite is modeled as elastic inclusions randomly dispersed throughout a viscoelastic matrix. It is also assumed that the spatial distribution of the inclusions in the composite is known or can be determined. Zevin's method of iterative functions is proposed for the determination of the matrix properties. Following a detailed explanation of the proposed scheme, a numerical verification is performed using three-dimensional finite-element (FE) analysis simulations. The proposed scheme was applied to the experimentally obtained creep compliance of the asphalt concrete beam. The obtained viscoelastic properties of the asphalt binder matrix phase were used as input into the FE model to simulate the behavior of the composite beam. An excellent comparison between the experimental data and the predicted beam deflections was observed. This shows that the proposed method is robust and it can be implemented to solve identification problems for viscoelastic composite materials. DOI: 10.1061/(ASCE)EM. 1943-7889.0000126 CE Database subject headings: Elasticity; Viscoelasticity; Numerical analysis; Asphalts; Mixtures; Composite materials; Pavements. Author keywords: Elasticity; Viscoelasticity; Numerical analysis; Asphalts; Mixtures; Composite materials; Pavements.

The Minnesota Department of Transportation began construction on the Minnesota Road Research Project (MnROAD) in 1991 and opened the full-scale pavement research facility to live traffic in 1994. Since the time of its construction, MnROAD, the first major test track since the AASHO Road Test of the 1950s and 1960s, has learned a number of lessons on behalf of the greater pavement community. As part of completing the first phase of MnROAD (its first ten years of operation), researchers at the University of Minnesota reviewed the many products of MnROAD's first phase for a project titled 'MnROAD Lessons Learned.' The Lessons Learned Project involved over fifty interviews, three hundred published and unpublished reports, papers, and briefs, and an online survey of pavement professionals. This paper, based on the Lessons Learned Project, presents an overview of MnROAD products of interest at the local, state, and national levels. Furthermore, the paper provides extensive references for these products in the hopes of increasing awareness of MnROAD's under-publicized contributions to pavement engineering. DOI: 10.1061/(ASCE)0733-947X(2007) 133:11 (599) CE Database subject headings: Pavement management; Databases; Minnesota.

This study considers a plate consisting of one or more layers, resting on a general clastic foundation, and subjected to a nonlinear through-the-thickness temperature distribution, together with arbitrary wheel loads. The resultant bending stress distribution in the plate is presented as the sum of the bending stresses due to the applied loading and to an equivalent linear temperature gradient, pius the pure thermal stresses due to the nonlinear part of temperature distribution. The resulting algorithm has been implemented into finite-element code ILSL2, capable of accommodating one- or two-layered slabs with a temperature distribution through the individual layers described by a linear function, a quadratic function, or explicitly provided by the user at a number of individual depths. Several examples are used to illustrate application of the method.

An algorithm for elastic reactions that can be used to compute other force or deformation variables was reviewed. This algorithm was then compared to a previous solution by Kharlab in 1963 that computes the response of structures undergoing continuous changes under time-dependent loads. This was based on his principle that if the superposition is satisfied, then (i + 1)th delayed restraint acts on the system like it was the first and only restraint.

Several tests are used for the characterization of unbound materials for pavement applications. The resilient modulus has been one of the most common tests for design specification of unbound materials. The California bearing ratio (CBR) is another laboratory test that is frequently used. The dynamic cone penetrometer (DCP) test is a more common test for in situ quality assessment/quality control of unbound materials. For better connection between design and quality assurance (QA)/quality control (QC), it would be helpful to have a reliable, mechanistic method for correlating test results. This is particularly true for the use of new materials, for which there is not an extensive body of data to empirically draw such connections. This paper presents a framework for a unified approach for modeling these tests. A discrete-element method (DEM) is used to simulate the CBR test, the DCP test, and the resilient modulus test. An initial evaluation demonstrated that the simulations can account for the effect of aggregate shape, size, gradation, friction, and stiffness. As such, this methodology shows promise for the development of mechanistic-based correlation between test results. These results are presented, along with some limitations of the current model and challenges for the future. [ABSTRACT FROM AUTHOR]

In practice, it has been observed that the method of pervious concrete void maintenance depends on which machines or vehicles the owners have available. This research compares the abilities of three common municipal utility vehicles-a vacuum truck with a flexible, 200-mm (8-in.) hose; a vacuum street sweeper; and a regenerative air street sweeper-to remove clogging material from the voids of in-service pervious concrete pavements. By using optical microscopy, it was found that clogging materials rarely migrate into voids deeper than 12.7 mm (1/2 in.) from the surface. Furthermore, all three machines were able to remove clogging materials that were located within 3.18 mm (1/8 in.) of the surface. The clogging material that was located deeper than 3.18 mm (1/8 in.) remained within the voids but was likely disturbed by either the suction or the forced air of the maintenance vehicles. [ABSTRACT FROM AUTHOR]