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High Performance Aggregates for Sustainable Road Pavements

English title High Performance Aggregates for Sustainable Road Pavements
Applicant Poulikakos Lily
Number 157122
Funding scheme Project funding (Div. I-III)
Research institution Eidg. Materialprüfungs- und Forschungsanstalt (EMPA)
Institution of higher education Swiss Federal Laboratories for Materials Science and Technology - EMPA
Main discipline Civil Engineering
Start/End 01.04.2015 - 31.07.2020
Approved amount 283'514.00
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Keywords (4)

Engineered Aggregates; Numerical Modelling; Discrete Element Method ; Extrusion Molding

Lay Summary (German)

Lead
Nachhaltige Strassenbeläge beruhen vermehrt auf Aufbereitung und Gebrauch von wiederverwendeten Materialen und auf die Verwendung von Materialien geringeren Wertes. Durch die Verknappung der Rohstoffe wird weltweit vermehrt auf dem Gebiet des Recyclings von Industrieabfällen geforscht. Immer mehr Fahrzeuge transportieren wirtschaftlich bedingt auf den Strassen immer schwerere Lasten. Dies verlangt nach einer robusteren Infrastruktur, die diese erhöhten Anforderungen bewältigen kann.
Lay summary

Strassenbeläge bestehen aus drei Komponenten: mineralische Zuschlagsstoffe, Bindemittel und Hohlräume, die einen direkten Einfluss auf die Eigenschaften des Materials ausüben. Die mineralischen Zuschlagsstoffe bilden ein Skelett, welches die Lasten auf die unteren Schichten in der Strasse überträgt. Die Zuschlagsstoffe spielen eine wesentliche Rolle in Bezug auf die Stärke und Dauerhaftigkeit von Strassenbelägen. Die Eigenschaft des Belages ist von den Materialien, der Gestaltung und des Herstellungsprozesses abhängig. Diese drei Aspekte werden in diesem Projekt genauer untersucht.

In diesem Projekt will man das Verhalten künstlich hergestellter Zuschlagsstoffe mittels Messungen, kombiniert mit Experimenten und Modellierung, ergründen, um die physikalischen Eigenschaften zu verstehen und mit neuen Erkenntnissen den Belag optimieren zu können. Von speziellem Interesse sind die Form und die Oberflächeneigenschaften der Zuschlagsstoffe für optimale Adhäsionseigenschaften, um die Dauerhaftigkeit der Strasse zu verbessern.

Direct link to Lay Summary Last update: 30.03.2015

Responsible applicant and co-applicants

Employees

Project partner

Collaboration

Group / person Country
Types of collaboration
Empa Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel

Associated projects

Number Title Start Funding scheme
166836 Additive manufacturing of pavements 01.03.2016 International short research visits
163394 Fundamental aspects of foam bitumen design and aggregate coating 01.03.2016 Project funding (Div. I-III)
140210 A Multi-Scale Investigation of Recycled Asphalt Concrete 01.09.2012 Project funding (Div. I-III)
169122 Bitumen Based Intrinsically Icephobic Road Surfaces 01.05.2017 Project funding (Div. I-III)
143651 Wetting and drying of porous asphalt pavement: a multiscale approach 01.02.2013 Project funding (Div. I-III)
178991 Urban Mining for Low Noise Urban Roads and Optimized Design of Street Canyons 01.01.2019 Project funding (Div. I-III)
152980 RECYCLING ASPHALT CONCRETE EXPLORING FUNDAMENTAL ASPECTS OF THE INTERFACES 01.09.2014 Project funding (Div. I-III)

Abstract

Sustainable road pavements need to rely increasingly on recycling, re-use of materials and use of marginal materials. Due to the increase in scarcity of raw materials, the use of industrial waste as aggregates in building materials has become the topic of widespread research worldwide. Furthermore, due to the ever increasing economic competitiveness, the loads transported by the pavements are increasing, demanding a more robust infrastructure that can handle these higher loads. Road materials consist of three constituents: mineral aggregates, binders and air voids and naturally the properties of asphalt concrete are a direct result of amount and quality of these constituents as well as their compatibility and interaction. The mineral aggregates create a skeleton that carries the load to the lower layers and play an important role in strength and durability of the road infrastructure. Performance of the aggregates is a function of materials, their geometry and production process. This project aims to address all three aspects.The majority of investigated artificial aggregates in road materials obtained from industrial waste fall into two categories. On the one hand artificial plastic based aggregates and on the other e.g fly ash and bottom ash resulting from incineration of solid waste have shown promising results as partial substitution for construction materials in general and road materials in particular. Currently, the traditional mixture design is based on conglomerate theory. Failure of asphalt concrete occurs under normal use either at the interface between the binder and the aggregates (adhesive failure) or within the binder (cohesive failure) and performance of the material is ultimately a function of adequate adhesion and cohesion.This project intends to develop optimum engineered artificial aggregates for use in road materials using a multi-scale approach combining experimental and modelling technique in order to understand the underlying physical properties at play for optimum pavement performance. To this end, superior performance is sought through the optimization of materials, including shape as well as optimization of surface features to improve wetting properties and the resulting adhesive properties. The possibilities to influence the shape of the aggregates will be investigated in order to influence anisotropy of pavements and optimum interlocking of the aggregates. Of particular interest is the engineered micro/macro- structural features necessary for superior performance of aggregates in asphalt concrete. Key surface properties such as surface roughness, contact angle between aggregate and bitumen and resulting adhesive properties will be investigated.The project is divided in two parts and aims to achieve its goals using a multi-scale approach. The focus of Part-A is the numerical simulations of asphalt concrete incorporating engineered aggregates while the focus of Part-B is the experimental investigation as input for the model developed in Part-A and as a verification means. Specifically, the goals of the project are:1.To seek methods to scale up quality of aggregates considered as marginal materials for road applications2.Understand mechanisms and identify key parameters as scientific basis for the above3.Investigate experimentally and theoretically optimal/alternative geometries of aggregates in order to improve performance of mixtures (length-height ratio 3D form) 4.To engineer the performance of asphalt by tailoring the properties of a certain fraction of aggregates5.Laboratory scale validation of engineered mixtures (mechanical/ durability)
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