Miljøvennlige vegdekker : spesialdekker - poroelastiske dekker

Arbeidspakke 9 i Miljøvennlige vegdekker prosjektet omhandler spesialdekker. Målet for arbeidspakken er å samle erfaringer og kunnskap om spesielle støysvake vegdekker slik som poroelastiske dekker og tynndekker som innholder polymermodifiserte bindemidler. Forskning om poroelastiske dekker har foregått i Japan og Sverige i mange år. Derfor ble kontakt tatt med forskere i disse landene for å få informasjon, dokumenter, og publikasjoner om poroelastiske vegdekker. Denne rapporten gir en kort sammenfatning av tilgjengelige litteratur om poroelastiske dekker

Performance Prediction Models for Flexible Pavements: A State-of-the-art Report

En av aktivitetene for forprosjektet til NordFoU prosjektet - "Pavement Performance Models" var gjennomgang og ekspertvurdering av eksisterende tilstandsutviklingsmodeller. Målet med å gjennomgå modellene var å finne ut styrkene og svakhetene av eksisterende modeller for å danne et grunnlag for en mer grundig vurdering, valg og forbedring av modellene. Undersøkelsen omfattet modeller som er i bruk i de nordiske landene samt noen relevante modeller fra de andre landene (europeiske land og USA). Denne statusrapporten viser resultatet fra gjennomgangen av modellene

Research on asphalt surface layer performance over service time and establishment of ageing model for in-service bitumen under Norwegian conditions

Asphalt surface layer as one of the significant pavement layers is directly withstanding traffic loading and external service conditions, and its performance highly determines the life cycle cost of asphalt pavements. Bitumen ageing is an unavoidable process for asphalt surface layer, and it shortens the service life and increases the risk of distress of asphalt pavements. A large number of studies have been conducted on the consequences of asphalt surface layer ageing under ambient environmental conditions. However, the development of asphalt mixture performance under Norwegian conditions and ageing model for the in-service bitumen have not been extensively investigated. Therefore, this work aims to investigate asphalt surface layer performance over service time and establish ageing model for the in-service bitumen. To achieve this goal, core samples acquired from the field and bitumen extracted from in-service field cores were analysed by comparing them with reference bitumen and asphalt mixtures. The physical, chemical, viscoelastic and performance grade variables of the bitumen were characterised, as well as the dynamic modulus and density of asphalt mixtures. The ageing models for bitumen property parameters were established using bitumen type, service time and average annual temperature as independent variables after statistical data processing. As a result, a good agreement between predicted values and measured values of property parameters was achieved because of the high accuracy of prediction of the ageing model. The proposed ageing model for bitumen under Norwegian conditions is beneficial for predicting bitumen properties at specific service time

Influence of material factors on the determination of dynamic moduli and associated prediction models for different types of asphalt mixtures

In a Mechanistic-Empirical (ME) pavement design system, the dynamic modulus is used to characterise asphalt mixtures, which are affected by many factors including environmental conditions and material properties. This study examined twenty types of asphalt mixtures containing nine types of bituminous binders that are commonly used for construction of road pavements in Norway. The objective of the study was to investigate the relationship between material factors and dynamic modulus. The dynamic moduli of asphalt mixtures were experimentally determined employing cyclic indirect tensile tests and were modelled with master curves implementing the sigmoidal function. The rheological properties of bitumen were characterised using a dynamic shear rheometer. The viscosity was simulated using a temperature-based log-linear relationship and the complex modulus was obtained based on the modified Huet-Sayegh model. The grey relational analysis revealed the correlation existing between the material factors and the dynamic modulus. A prediction model was established using a Multiple Linear Regression (MLR). The results indicate that the dynamic modulus of asphalt mixtures is greatly affected by the following parameters ranked in order of decreasing significance: viscosity and complex modulus of the binder, void filled with bitumen, air void content, bitumen penetration and softening point. Based on the MLR model, the correlation between the dynamic modulus and the bitumen viscosity and complex modulus fit well with Coefficient of Determination (R2) ≥ 0.901. The determination of the sigmoidal function parameters to predict the dynamic modulus had good reliability with R2 ≥ 0.973. This study contributes to the development of an accurate and convenient method to predict the dynamic moduli of asphalt mixtures based on the material factors for a ME pavement design system.publishedVersio