Examinando Artículos Ingeniería por Autor "Alabaster, David"
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- ÍtemElastic strains, modulus and permanent deformation of foamed bitumen pavements in accelerated testing facility(2012) González Vaccarezza, Álvaro; Cubrinovski, Misko; Pidwerbesky, Bryan; Alabaster, DavidAn accelerated full-scale experiment on foamed bitumen (FB) pavements was conducted at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF) in New Zealand. The results of the CAPTIF experiment showed that the section with 2.8% bitumen content and 1% cement content (section B28C10) had the best performance. These results were published in a previous research paper. The current paper is the continuation of the previous work and aims to provide design and performance parameters that could be used by practitioners and researchers. The pavement strains were measured at different depths and transverse locations using pavement instrumentation. The measurements showed that subgrade strains are lower in section B28C10 and that the strain distribution in the subgrade is relatively uniform, reducing the strain concentrations in this layer. Falling Weight Deflectometer (FWD) measurements were used to determine an AASHTO 93 structural coefficient of 0.20 for the FB layer of section B28C10. FWD and pavement strain measurements were used to back-calculate the average elastic modulus of 1100 MPa for the FB layer. Finally, a permanent or plastic strain model was developed for the FB layer using the pavement vertical surface deformation measurements and post-mortem data.
- ÍtemInterpretation of laboratory and full-scale testing of New Zealand foamed bitumen pavements using finite-element modelling(2012) González Vaccarezza, Álvaro; Cubrinovski, Misko; Alabaster, David; Thenoux, GuillermoA large research project on foamed bitumen (FB) stabilisation was conducted in New Zealand. The project consisted of an extensive laboratory and full-scale testing of FB pavements. The objective of this paper is to interpret the performance of FB pavements by using finite-element (FE) modelling. The mechanical properties of the materials were calculated using testing data and used as material inputs in the FE modelling. The MohrCoulomb and DruckerPrager material models were adopted to calculate plastic deformation, which is related to pavement rutting. Results of the modelling indicate that increasing the FB content increases the tensile strength and modulus of the pavements, reducing the plastic deformations in the subgrade and the stabilised layer. In addition, adding FB reduces sensitivity to rutting when pavement is overloaded or the asphalt surface layer is cracked
- ÍtemPerformance of foamed bitumen pavements in accelerated testing facility(2012) Cubrinovski, Misko; Gonzalez, Alvaro; Pidwerbesky, Bryan; Alabaster, DavidOne of the key principal goals of pavement asset management is to develop and implement cost-effective pavement construction and maintenance strategies that achieve the required levels of service and performance. A sustainable, cost-effective technique for rehabilitating pavements is foamed bitumen stabilization. This paper presents a study on the performance of foamed bitumen pavements tested in the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF), for full scale testing of pavements. Six pavement sections were tested; the variables were bitumen and cement content; one control section with the untreated unbound material was tested. Results showed that surface deflections decreased at sections with higher bitumen contents. After the application of 5,710,000 Equivalent Standard Axles (ESAs), the sections stabilised with cement only, bitumen only, and the control section all showed large amounts of rutting. Conversely, little rutting was observed in the three sections stabilised with foamed bitumen and 1.0% cement, showing that cement and FB together significantly improve pavement performance. The rutting results were used to develop models to describe the stable and unstable performance of the tested pavements. The paper concludes by outlining some of the practical benefits of utilising this technology in pavement asset management.