Pavement Information Modelling (PIM): Best Practice to Build a Digital Repository for Roads Asset Management

The application of BIM methods and tools plays a key role in transportation infrastructure asset management. Road pavements represent one of the main components of the asset, which greatly influences safety and quality of service for users. The work presented herein exploited the potentialities of BIM processes and methods for management of road pavement structures. The specific goal was to define best practice for development of a methodological framework for Pavement Information Modelling (PIM). The starting point of the process was the identification of the specific BIM use, as intended by Kreider and Messner [1]. In this case, the BIM use identified concerned the 3rd (3D), 4th (4D), and 5th (5D) dimensions of BIM. The adopted approach had the aim to define the steps to build PIM based on geometrical and structural parameters to be used as a database for different kinds of maintenance strategies. Within this context, the main objectives of the study can be summarized as follows:(1)Define the steps to develop a PIM including all the relevant information to be stored for management purposes, from data collection to data restitution,(2)Define a best practice for the integration among BIM tools and road pavement management methods in order to obtain a digital repository for predictive maintenance strategies,(3)Define a planning and cost database for the different technologies and materials involved in the different maintenance strategies.From a practical point of view, the methodological framework was divided into three main categories (Figure 1) dealing with data: (i) data collection and input definition, which includes the analysis of available data and the BIM tools to be used to develop specific workflows; (ii) data processing, by dividing the workflows and related tasks in sub-sections for the fulfilment of the previously enounced objectives; (iii) data output, by defining the final result of each workflow.QC 20230706</p

Evaluation of the anti-rutting potential of polymer-modified binders by means of creep-recovery shear tests

In the experimental study reported in this paper a creep-recovery shear test method was used to evaluate the anti-rutting potential of different polymer-modified bituminous binders. The effects of several factors related to modification were investigated, such as polymer type (SBS, Styrene-Butadiene-Styrene vs. EVA, Ethylene-Vinyl-Acetate), composition (styrene content), structure (linear vs. radial SBS) and dosage (3-6% by weight of the base bitumen). The effect of short-term aging was also considered by comparing binder response before and after treatment with the Rolling Thin-Film Oven Test (RTFOT). Following previous work on the development of the test protocol, experimental results were analyzed by referring to shear modulus curves G(t) and to permanent compliance (JP), obtained by dividing residual strain at the end of the unloading phase by the stress applied during creep loading. Results indicated the effectiveness of the proposed method in discriminating between the behavior of the different polymer-modified binders and in capturing the effects caused by the factors considered in the investigation. Reliable rankings of the binders were established and were explained by referring to the specific behavior of employed modifiers

Investigating cohesive healing of asphalt binders by means of a dissipated energy approach

The paper reports the results of an experimental investigation in which the cohesive healing properties of different types of asphalt binder were evaluated by means of the dissipated energy ratio approach. A specifically designed testing methodology was proposed which involves comparing the response of binders subjected to continuous oscillatory shear loading carried out without rest periods and with single rest periods introduced at predefined levels of damage A rheological parameter (Healing Ratio) was introduced to quantify the magnitude of healing occurring during rest time and to rank the consequent healing potential of binders. Obtained results indicate that the investigated binders did not completely recover their original fatigue resistance after rest time, confirming the existence of some intrinsic irreversible damage, the amount of which depends on the total damage experienced before load removal. Experimental results also indicate that healing performance of binders can be significantly enhanced by polymer modification. Keywords: Healing, Fatigue, Dissipated energy ratio, Asphalt binder, Polymer modificatio

Correlating creep properties of bituminous binders with anti-rutting performance of corresponding mixtures

In the experimental study described in this paper, rutting properties of different bituminous binders and those of corresponding mixtures characterized by common composition and volumetrics were investigated and compared. Single shear creep-recovery (SSCR) tests were carried out on binders for the determination of their creep compliance rate (CCR), whereas bituminous mixtures were evaluated by referring to their Flow Number (FN), derived from repeated compressive loading tests. Analysis of experimental data revealed the existence of a strong correlation between rutting parameter of binders and permanent deformation response of mixtures. This confirmed the potential of the proposed testing procedure of being adopted for the evaluation of rutting properties of bituminous binders and for their consequent perfomance-related ranking

Use of Municipal Solid Waste Bottom Ashes in Rubberized Asphalt Mixtures

The increasing need of environment protection and preservation has been stimulating road agencies to progressively adopt sustainable technologies for the design, construction, and maintenance of their assets, with the consequent increasing use of recycled materials, industrial by-products, and wastes. In such a context, the experimental investigation presented in this paper moved from the idea of synergistically combining the use of bottom ashes originating from incineration of municipal solid waste (MSW) and crumb rubber from end-of-life tires. The performance-related properties of rubberized asphalt mixtures containing MSW bottom ashes in partial substitution of natural aggregates were evaluated by means of laboratory tests focused on the determination of workability, viscoelastic characteristics, antirutting potential, and resistance to crack propagation. Tests were carried out by considering an ash-amended rubberized asphalt mixture and, for comparison purposes, a standard gap-graded rubberized mixture (GGRM). Obtained results indicate that the rubberized mixture containing bottom ashes exhibited lower workability (16 % decrease in k parameter), reduced stiffness (decrease of dynamic modulus at 20°C of approximately 40 % and 60 % at 0.1 Hz and 10 Hz, respectively), and decreased anti-rutting potential (17 % decrease in flow number values) with respect to the standard GGRM. Conversely, the addition of bottom ashes was found to provide beneficial effects in terms of resistance to crack propagation (with fracture toughness values five times larger than those of the reference mixture). These outcomes suggest that the use of MSW bottom ashes must be carefully considered because environmental benefits may be counterbalanced by lower performance

Triaxial Testing for the Short Term Evaluation of Cold-Recycled Bituminous Mixtures

The experimental investigation described in this paper refers to the performancerelated characterization of cold-recycled bituminous mixtures employed for the construction and maintenance of road pavements. One of the most critical issues that have to be examined for these mixtures is their short term behaviour under loading, since in the early phases after laying they are more similar to unbound granular materials than to traditional hot bituminous mixtures. In such a context, the authors carried out triaxial tests on a reference cold-recycled mixtures by employing the equipment generally recommended for subgrade soils and foundation materials. Slender laboratory compacted specimens, prepared by means of a gyratory shear compactor, were subjected to triaxial tests for the determination of resilient modulus and of shear strength parameters at three different temperatures (20, 40 and 60°C) and in three different curing conditions (short term, intermediate and full curing). The obtained results were analyzed according to models already available in literature and were discussed by taking into account the internal structure and composition of the mixtur

Fatigue and healing properties of bituminous mastics reinforced with nano-sized additives

The research work described in the paper focused on fatigue and healing properties of bituminous mastics reinforced with nano-sized additives. Commercially available multiwall carbon nanotubes (CNTs) and montmorillonite nanoclay (NC) were combined with a single base bitumen and a standard mineral filler to produce bituminous mastics. These blends were prepared in the laboratory by making use of a technique consisting in simple shear mixing followed by sonication. Fatigue behaviour of mastics under repeated loading was investigated by means of time sweeps performed in the strain-controlled mode at various amplitudes. Healing potential was assessed by adopting a testing protocol specifically conceived to discriminate between recovery of damage induced by fatigue loading and other artefact phenomena which may affect material response. All rheological measurements were carried out with a dynamic shear rheometer in the parallel plates geometry. Outcomes of the experimental investigation were found to be highly dependent on the nature of additive type, as a result of the key role played by interaction mechanisms that nano-particles can establish within the bituminous mastic

A novel methodology for the evaluation of low temperature failure properties of asphalt binders

This paper presents the results of an experimental investigation that focused on the failure properties of asphalt binders at low temperatures. A novel test method was developed, based on the use of the dynamic shear rheometer equipped with 4 mm parallel plates. The method entails the application of constant shear strain rates at various temperatures until failure. Test data are modelled by means of the elasticviscoelastic correspondence principle and by thereafter referring to the shear stress at failure, to a purposely defined brittleness index and to a critical brittleness temperature. Results discussed in the paper, which refer to a preliminary set of experimental data, indicate that the proposed methodology may be very effective in evaluating and comparing low temperature failure properties of asphalt binders of various types and origins

Life Cycle Assessment of a Sustainable and Innovative Solution for Unpaved Rural Roads

The use of recycled aggregates, including waste materials and by-products, has attracted increasing interest in the last decades as a sustainable and cost-effective solution for the construction and maintenance of road pavements, due to the reduction of excavation operations and depletion of natural resources. Life cycle assessment (LCA) represents a valuable methodology for the evaluation of the environmental sustainability of technologies involving the use of such materials. This paper deals with the LCA of an innovative emulsion-based cold recycled mixture specifically conceived to be used as a sustainable solution for the surface finishing of unpaved rural roads. Two scenarios entailing the employment of recycled or virgin materials were analyzed with the assessment of global warming potential (GWP), energy requirement, and water consumption. Results obtained confirmed that the scenario entailing the use of recycled materials represents the most sustainable and environmentally friendly solution

Effect of sonication on high temperature properties of bituminous binders reinforced with nano-additives

The study focused on the effect of sonication on high temperature properties of bituminous binders containing carbon nanotubes and nanoclays. Blends at various dosages were prepared in the laboratory according to two techniques, based on sonication and/or shear mixing. Rheological behaviour of binders was investigated, in the unaged and short-term aged state, by means of oscillatory and creep–recovery tests. Experimental results were found to be coherent with interaction phenomena occurring at the nano-scale and indicate that effects caused by sonication on nano-modified blends are not univocal, but are highly dependent on additive type