Non-Destructive Evaluation of Asphalt Concrete Materials Performance During their Life Cycle Based on Accelerated Pavement Testing

The characteristics of asphalt concrete materials (ACM) composing the surfacing layer of a bituminous pavement must fulfil a requirement to maintain a level of operational capability demanded by national standards of a given country. ACM’s are a subject to significant stress caused by traffic load and climate conditions, this leads to changes in their physico-mechanical properties. The loss of physico-mechanical properties causes deterioration of road surface characteristics. Since these changes occur throughout the ACM’s life cycle, it is necessary to know the deterioration curves related to loading and time in mathematical terms, i.e. functions describing the initiation and progression of pavement’s defect in time. Pavement Performance Models (PPM) ascertained by non-destructive testing are used to objectively express the surface properties of pavements and their deterioration. The methodology consists of an analytical method to ascertain physico-mechanical characteristics of ACM’s and the use of experimental accelerated pavement testing (APT) facilities.

A Review of Accelerated Pavement Testing Applications in Non-Pavement Research

Accelerated pavement testing (APT) facilities has been demonstrated for years as a multi-purpose solution for pavement and non-pavement research. Even though APTs are widely known in the pavement industry, little has been publicized about their successful applications in non-pavement research. This paper provides a survey of APT applications in non-pavement research. The purpose of the survey is to review and encourage APT owners and agencies to explore the opportunities that APT facilities can present to promote non-pavement research initiatives. The survey demonstrates the ability of APTs to conduct research for bridges, transportation technology, drainage, geotechnical engineering, automobiles, environmental engineering, highway safety, among others. Non-pavement research can be incorporated into APT programs to diversify funding sources for research operations and promote cooperation with other agencies. Finally, suggestions for future and current APTs are made in this paper, including evaluating connected vehicles, work zone applications, smart infrastructure, truck platooning effects on bridge performance, sustainable drainage systems, bridges, advancement in geotechnical methods, sustainable fuels, and unmanned aerial systems.

Development of Piezoelectric Energy Harvester System through Optimizing Multiple Structural Parameters

Road power generation technology is of significance for constructing smart roads. With a high electromechanical conversion rate and high bearing capacity, the stack piezoelectric transducer is one of the most used structures in road energy harvesting to convert mechanical energy into electrical energy. To further improve the energy generation efficiency of this type of piezoelectric energy harvester (PEH), this study theoretically and experimentally investigated the influences of connection mode, number of stack layers, ratio of height to cross-sectional area and number of units on the power generation performance. Two types of PEHs were designed and verified using a laboratory accelerated pavement testing system. The findings of this study can guide the structural optimization of PEHs to meet different purposes of sensing or energy harvesting.

Evaluation of Cost-Effective Modified Binder Thin Chip and Cape Seal Surfacings on an Anionic Nano-Modified Emulsion (NME)-Stabilised Base Layer Using Accelerated Pavement Testing (APT)

Emulsion stabilisation of base layers surfaced with chip seals often proves problematic, with chips punching into the base and early distress. This can be aggravated by the use of modified binders that restricts the evaporation of moisture from pavement layers. The introduction of new-age (nano)-modified emulsion (NME) stabilisation has the advantage that water is chemically repelled from the stabilised layer, resulting in an accelerated development of strength. A need was identified to evaluate the early-life performance of selected chip and Cape seals, together with identified modified binders on anionic NME-stabilised base layers constructed with materials traditionally classified as unsuitable, using archaic empirically derived tests. Three different chip seal surfacings with unconventional modified binders were constructed and evaluated using accelerated pavement testing (APT) with the Model Mobile Load Simulator—3rd model (MMLS3). The objectives of the experimental design and testing were to evaluate the binder performance, chip seal performance in terms of early loss of chips before chip orientation, punching of the chips into the anionic NME-stabilised base and deformation characteristics of a Cape seal that was hand-laid using an anionic NME slurry without any cement filler. It was shown that that chip seal surfacings can be used at low risk, on a base layer containing materials with fines exceeding 22%. The selection of specific modified binders can reduce risks associated with chip seal surfacings, which can impact construction limitations. The recommended use of elastomer-modified binders on newly constructed or rehabilitated layers, resulting in moisture entrapment, needs to be reconsidered.