Periodic Reporting for period 1 - FHBMicro (Fatigue Damage and Healing of Bituminous Materials: from Microscopic Mechanism towards Lifetime Extension)
Période du rapport: 2021-04-01 au 2023-03-31
Bituminous materials (BMs) including bitumen and asphalt are considered the primary components of a modern pavement structure and have been used to construct and maintain over 90% of the 5.2 million km of paved roads and highways in Europe. The BMs exhibit significantly complex characteristics due to bitumen cohesion, bitumen-aggregate adhesion, the inclusion of air voids and inherent defects in the mixtures. Fatigue damage (e.g. cracking) of the BMs can occur under repeated traffic loads and changeable environmental conditions. After long rest periods and/or exposure to high temperatures, the accumulated damage is partially or fully recovered through the closure of the cracks (i.e. healing). Most of the existing studies were focused on the macroscopic experimental characterisation and numerical simulations of the BMs’ fatigue damage and healing and their underlying mechanisms at the microscale are currently unknown. Therefore, an increasing demand has been raised for a comprehensive understanding of the microscopic mechanisms leading to the fatigue damage and healing of the BMs to fundamentally extend the roads’ service life.
The objectives of this project included: 1) training of the Fellow’s academic expertise, professional skills and cross-disciplinary collaboration; 2) investigating microscopic mechanisms of the BMs’ fatigue damage and healing; 3) modelling microscopic behaviours of fatigue damage and healing and multiscale performance prediction of the BMs; 4) development and evaluation of the anti-fatigue and self-healing BMs and technologies; and 5) industrial application of the anti-fatigue and self-healing materials and evaluation technologies for the BMs. The research work significantly contributes to extending the road service life, reducing road maintenance costs and greenhouse gas emissions and saving natural resources like petroleum bitumen.
The objectives of this project included: 1) training of the Fellow’s academic expertise, professional skills and cross-disciplinary collaboration; 2) investigating microscopic mechanisms of the BMs’ fatigue damage and healing; 3) modelling microscopic behaviours of fatigue damage and healing and multiscale performance prediction of the BMs; 4) development and evaluation of the anti-fatigue and self-healing BMs and technologies; and 5) industrial application of the anti-fatigue and self-healing materials and evaluation technologies for the BMs. The research work significantly contributes to extending the road service life, reducing road maintenance costs and greenhouse gas emissions and saving natural resources like petroleum bitumen.
The work was performed during the duration of the fellowship through the following five work packages (WPs) in the FHBMicro project.
WP1: Overall training-through-research. The transfer of knowledge was well achieved through extensive training activities during the fellowship. The scientific knowledge training was carried out to enhance the Fellow’s expertise in microscopic technologies, multiscale modelling and experimental characterisation. Through the complementary skill training, the Fellow’s qualification was promoted in terms of project management, open science, teaching & supervision, networking and communication. The Fellow gave three presentations to the students and academic staff at the host and partner institutions and supervised two PhD students. Main output: a well-trained researcher with competitive scientific knowledge and professional skills.
WP2: Microscopic mechanisms of BMs’ fatigue damage and healing. The fundamental chemical and physical properties of the materials including the chemical composition, microstructural morphology and surface energy of the BMs were tested and analysed using Fourier transform infra-red (FTIR) spectroscopy, scanning electron microscopy (SEM) and optical tensiometer. Furthermore, the fatigue damage and healing tests of the BMs were conducted with a dynamic shear rheometer (DSR) and the inter-relationship between the fundamental material properties and the damage and healing was investigated to interpret the microscopic mechanisms. Main outputs: Two papers were published in academic journals (i.e. Cellulose and TRR). One presentation was delivered at IACIP Conference. One poster was presented at TRB Conference.
WP3: Multiscale modelling and performance prediction for fatigue damage and healing of BMs. At the microscale, the fundamental material properties (i.e. chemical composition, diffusion, surface energy and intrinsic strength) were predicted and the molecular behaviours of fatigue damage and healing (i.e. molecular rearrangement and inter-diffusion) were characterised using molecular dynamics (MD) simulations. The results obtained from the MD simulations were integrated into the macroscopic crack-based models developed by fracture and damage mechanics. Finally, a multiscale performance prediction framework was developed to predict the fatigue and healing performance of the BMs. Main outputs: Five papers were published in academic journals (i.e. CBM, Mater. Des., JTTE, Fuel and Cellulose). One paper was under review. One presentation was delivered at TRC Conference. One presentation will be delivered at CEW Conference.
WP4: Development and evaluation of anti-fatigue and self-healing BMs. The anti-fatigue and self-healing BMs were developed by using the anti-ageing compounds, cow dung fibre and rejuvenators in the bitumen. The fatigue and healing tests were performed under varying ageing and temperature conditions to evaluate their fatigue damage and healing performance. An evaluation protocol was established to examine the effectiveness of the anti-fatigue and self-healing BMs. Main outputs: Two papers were published in academic journals (i.e. Cellulose and Mater. Des.).
WP5: Industry applications and feedback. The anti-fatigue and self-healing BMs and a performance evaluation approach were introduced and trialled in industry practices. The Fellow visited the industry partner institutions and further collaborations were built between them. Main outputs: Two seminars and one workshop were organised at the different institutions.
WP1: Overall training-through-research. The transfer of knowledge was well achieved through extensive training activities during the fellowship. The scientific knowledge training was carried out to enhance the Fellow’s expertise in microscopic technologies, multiscale modelling and experimental characterisation. Through the complementary skill training, the Fellow’s qualification was promoted in terms of project management, open science, teaching & supervision, networking and communication. The Fellow gave three presentations to the students and academic staff at the host and partner institutions and supervised two PhD students. Main output: a well-trained researcher with competitive scientific knowledge and professional skills.
WP2: Microscopic mechanisms of BMs’ fatigue damage and healing. The fundamental chemical and physical properties of the materials including the chemical composition, microstructural morphology and surface energy of the BMs were tested and analysed using Fourier transform infra-red (FTIR) spectroscopy, scanning electron microscopy (SEM) and optical tensiometer. Furthermore, the fatigue damage and healing tests of the BMs were conducted with a dynamic shear rheometer (DSR) and the inter-relationship between the fundamental material properties and the damage and healing was investigated to interpret the microscopic mechanisms. Main outputs: Two papers were published in academic journals (i.e. Cellulose and TRR). One presentation was delivered at IACIP Conference. One poster was presented at TRB Conference.
WP3: Multiscale modelling and performance prediction for fatigue damage and healing of BMs. At the microscale, the fundamental material properties (i.e. chemical composition, diffusion, surface energy and intrinsic strength) were predicted and the molecular behaviours of fatigue damage and healing (i.e. molecular rearrangement and inter-diffusion) were characterised using molecular dynamics (MD) simulations. The results obtained from the MD simulations were integrated into the macroscopic crack-based models developed by fracture and damage mechanics. Finally, a multiscale performance prediction framework was developed to predict the fatigue and healing performance of the BMs. Main outputs: Five papers were published in academic journals (i.e. CBM, Mater. Des., JTTE, Fuel and Cellulose). One paper was under review. One presentation was delivered at TRC Conference. One presentation will be delivered at CEW Conference.
WP4: Development and evaluation of anti-fatigue and self-healing BMs. The anti-fatigue and self-healing BMs were developed by using the anti-ageing compounds, cow dung fibre and rejuvenators in the bitumen. The fatigue and healing tests were performed under varying ageing and temperature conditions to evaluate their fatigue damage and healing performance. An evaluation protocol was established to examine the effectiveness of the anti-fatigue and self-healing BMs. Main outputs: Two papers were published in academic journals (i.e. Cellulose and Mater. Des.).
WP5: Industry applications and feedback. The anti-fatigue and self-healing BMs and a performance evaluation approach were introduced and trialled in industry practices. The Fellow visited the industry partner institutions and further collaborations were built between them. Main outputs: Two seminars and one workshop were organised at the different institutions.
The new anti-fatigue and self-healing BMs and multiscale performance prediction approach were developed in this project. The project led to a number of publishable scientific results (e.g. journal articles and conference proceedings) and applicable industry practices (e.g. performance evaluation protocol). The project helped the Fellow achieve his mid-term career goal of obtaining a university faculty position in the UK. The training performed in this project extended the Fellow’s expertise from mechanics and simulations to chemistry, microscopic characterisation and material science coupled with valuable professional skills such as project management, networking and communication.
These new materials and methods developed in this project are expected to extend the roads’ service life. The research significantly contributes to reducing road maintenance costs and greenhouse gas emissions and saving natural resources like petroleum bitumen. The results of the project were disseminated and published to the most extent via multiple communication platforms such as journal publications, conference presentations and so on, targeting a variety of potential users and partners including researchers, engineers, road material companies and construction contractors throughout Europe and the world. The host institution organised a series of outreach activities to encourage a great interest in science among the university, school students and the general public. The benefits brought by this project are represented by enhancing the innovation of durable and sustainable road materials in the EU.
These new materials and methods developed in this project are expected to extend the roads’ service life. The research significantly contributes to reducing road maintenance costs and greenhouse gas emissions and saving natural resources like petroleum bitumen. The results of the project were disseminated and published to the most extent via multiple communication platforms such as journal publications, conference presentations and so on, targeting a variety of potential users and partners including researchers, engineers, road material companies and construction contractors throughout Europe and the world. The host institution organised a series of outreach activities to encourage a great interest in science among the university, school students and the general public. The benefits brought by this project are represented by enhancing the innovation of durable and sustainable road materials in the EU.