Advanced Testing and Characterization of Bituminous Materials, Two Volume Set

Bituminous materials are used to build durable roads that sustain diverse environmental conditions. However, due to their complexity and a global shortage of these materials, their design and technical development present several challenges. Advanced Testing and Characterisation of Bituminous Materials focuses on fundamental and performance testin

Advanced Testing and Characterization of Bituminous Materials, Two Volume Set

Bituminous materials are used to build durable roads that sustain diverse environmental conditions. However, due to their complexity and a global shortage of these materials, their design and technical development present several challenges. Advanced Testing and Characterisation of Bituminous Materials focuses on fundamental and performance testin

Peridynamic and discrete multiphysics for modelling the mechanical and fracture properties of pavement materials

Asphalt pavement experiences different degradation mechanisms under several solicitations. The asphalt mechanical and fracture properties of asphalt mixtures have been investigated using experiment and X-ray CT scan to improve the quality of design. These methods are limited by the number of samples required and high cost. The development of numerical methods provided a powerful tool to investigate the asphalt mixture performance at macro and micro scale, requiring lower number of sample and cost. A key challenge of the numerical method is the reliable modelling of the cracks under different conditions. In this thesis, Peridynamics and Discrete Multiphysics model is used to simulate the mechanical properties and fracture characteristics of pavement materials. The simulations were carried out on the open-source software LAMMPS and visualised on Ovito. Initially, the capability of Peridynamics and Discrete Multiphysics was explored to assess micro-crack formation and propagation in asphalt mixture at low temperatures and under freezing conditions. The results showed the cracks form at the interface and propagate from one void to another along the direction of load. In addition, the water expansion increases the pressure within the voids which adversely has a detrimental effect on the asphalt mixture performance. Experimental studies on three different asphalt mixtures with voids content of 3%, 10%, and 14% were performed at low temperature and freeze-thaw cycle to establish a correlation between the asphalt mixtures’ properties and the voids’ topology. The asphalt mixtures were scanned using Computer Tomography scan to determine the internal structure that evolves during freezing cycles. Semi-circular bending test was used to determine mechanical properties at low temperatures. The results show that asphalt mixture with 3% void content has the lowest and steady degradation rate with the lowest water retention during all cycles. The asphalt mixtures with a 3 high void content have the highest concentration of water in the pores and decay faster during the initial cycles, but slower during the later cycles because there is less water inside the pores which are fully open and do not retain it. A 3D model was used to simulate the asphalts mechanical and fracture properties discussed in the previous chapter at -10 °C. In addition to the previous chapter, asphalt mixtures mechanical and fracture properties at 20 °C were simulated. The results showed that the asphalt mixture performance is reproduced with 23.08% error for the asphalt mixture at -10 °C and 6.9% for the asphalt mixture at 20 °C compared to the experiments. The damage at low and high temperatures such as cracking was reproduced like the real sample. In addition, higher stress occurs in the area where damage was formed

Recent Advances and Future Trends in Pavement Engineering

This Special Issue “Recent Advances and Future Trends in Pavement Engineering” was proposed and organized to present recent developments in the field of innovative pavement materials and engineering. The 12 articles and state-of-the-art reviews highlighted in this editorial are related to different aspects of pavement engineering, from recycled asphalt pavements to alkali-activated materials, from hot mix asphalt concrete to porous asphalt concrete, from interface bonding to modal analysis, and from destructive testing to non-destructive pavement monitoring by using fiber optics sensors. This Special Issue partly provides an overview of current innovative pavement engineering ideas that have the potential to be implemented in industry in the future, covering some recent developments

Advances in Asphalt Pavement Technologies and Practices

Unlike other construction materials, road materials have developed minimally over the past 100 years. However, since the 1970s, the focus has been on more sustainable road construction materials such as recycled asphalt pavements. Recycling asphalt involves removing old asphalt and mixing it with new (fresh) aggregates, binders, and/or rejuvenators. Similarly, there are various efforts to use alternative modifiers and technical solutions such as crumb rubber, plastics, or various types of fibres. For the past two decades, researchers have been developing novel materials and technologies, such as self-healing materials, in order to improve road design, construction, and maintenance efficiency and reduce the financial and environmental burden of road construction. This Special Issue on “Advances in Asphalt Pavement Technologies and Practices” curates advanced/novel work on asphalt pavement design, construction, and maintenance. The Special Issue comprises 19 papers describing unique works that address the current challenges that the asphalt industry and road owners face

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

Behaviour of sandy soil subjected to dynamic loading

This thesis presents the kinematics occurring during lab-based dynamic compaction tests using high speed photography and image correlation techniques. High speed photography and X-ray microtomography have been used to analyse the behaviour of sandy soil subjected to dynamic impact. In particular, the densification mechanism of granular soils due to dynamic compaction is the main theme of the thesis. High speed photography and digital image correlation (DIC) techniques have enabled the deformation patterns, soil strains and strain localisations to be observed. Image correlation and X-ray scans revealed the formation, rate and growth of narrow tabular bands of intense deformation and significant volumetric change and provided answers towards a better understanding of the densification mechanism in dry granular soils due to dynamic compaction. As a quantitative tool, high speed photography has allowed the propagation of localised deformation and strain fields to be identified and has suggested that compaction shock bands control the kinematics of dynamic compaction. The displacement and strain results from high speed photography showed that soil deformation in the dynamic tests was dominated by a general bearing capacity mechanism similar to that widely stated in classic soil mechanics texts. Comparative static loading tests have been conducted to enable the dynamic effects to be clearly distinguished. This has enabled the densification process taking place below the soil surface to be investigated and identified. Simulations of the physical models were carried out using LS-DYNA finite element formulations for comparison and verification purposes. The FE simulations verified the general characteristics from the photography findings. However, simulation results were unable to predict the exact details of the strain localisation due to surface impacts during physical model tests

Behaviour of sandy soil subjected to dynamic loading

This thesis presents the kinematics occurring during lab-based dynamic compaction tests using high speed photography and image correlation techniques. High speed photography and X-ray microtomography have been used to analyse the behaviour of sandy soil subjected to dynamic impact. In particular, the densification mechanism of granular soils due to dynamic compaction is the main theme of the thesis. High speed photography and digital image correlation (DIC) techniques have enabled the deformation patterns, soil strains and strain localisations to be observed. Image correlation and X-ray scans revealed the formation, rate and growth of narrow tabular bands of intense deformation and significant volumetric change and provided answers towards a better understanding of the densification mechanism in dry granular soils due to dynamic compaction. As a quantitative tool, high speed photography has allowed the propagation of localised deformation and strain fields to be identified and has suggested that compaction shock bands control the kinematics of dynamic compaction. The displacement and strain results from high speed photography showed that soil deformation in the dynamic tests was dominated by a general bearing capacity mechanism similar to that widely stated in classic soil mechanics texts. Comparative static loading tests have been conducted to enable the dynamic effects to be clearly distinguished. This has enabled the densification process taking place below the soil surface to be investigated and identified. Simulations of the physical models were carried out using LS-DYNA finite element formulations for comparison and verification purposes. The FE simulations verified the general characteristics from the photography findings. However, simulation results were unable to predict the exact details of the strain localisation due to surface impacts during physical model tests