Comparison of numerical predictions for early-age creep

Creep at early ages significantly affects the volumetric deformation of cementitious materials. Efficient modelling of early-age creep is a challenging task, mainly due to continuously evolving material properties (hydration) and other phenomena (e.g. autogenous shrinkage) taking place in parallel. Various methods were introduced during the past...

Multi-phase modelling of multi-species transport in concrete: In case of electrochemical protection for both ASR and chloride attack

Existing reinforced concrete structures experience severe durability degradation when subjected to alkali–silica reaction (ASR) and chloride attack. A special electrochemical rehabilitation treatment, containing lithium compound anolyte, has been developed to drive lithium ions into concrete as well as remove chlorides simultaneously, for...

Thermodynamic modelling of the reactions of self-healing agents and the chemical binding of aggressive ions in seawater

In this study, a new concept on self healing of cracks that the ingressive ions in the crack is chemically bound to improve the self-healing efficiency was proposed for cracked cementitious materials in a marine environment. Thermodynamic modeling was performed to determine the appropriate masses and ratio of Ca2+ and Al3+ provided by chemical...

The influence of lightweight functional aggregates on the acidification damage in the external anode mortar during cathodic protection for reinforced concrete

Impressed current cathodic protection (ICCP) is an effective corrosion protection and prevention technique for reinforced concrete structures served in chloride-contaminated environment. The acidification damage in the external anode mortar caused by the anodic reactions significantly influences the efficiency of ICCP for reinforced concrete....

Closing the loop of EOL concrete

Production of waste materials, via industrial and human activities, creates big environmental and economic problems but also opportunities to recover valuable resources. EU28 currently generates 461 million tons per year of ever more complex Construction and Demolition Waste (CDW) with average recycling rates of around 46%. There is still a...

Life cycle assessment and life cycle costing for demolition waste management

Ninety five percent of the construction and demolition waste is recycled in the Netherlands. Most of it is used for low value applications such as road base materials; the use of secondary material in buildings is still less than 3%7. In order to recover waste for higher value applications, enhancing selective demolition and waste management...

Transition to turbulence in a qblique shock-wave/boundary-layer interaction at M=15

Direct numerical simulations are carried out for different forcing techniques to trigger transition during the interaction between an oblique shock-wave and a laminar boundary-layer at M = 1.5. Three forcing methods are used: a) forcing of oblique unstable modes, whose shape and behaviour are determined by the local linear stability theory, b)...

Calibration of a model to predict the Peak Punch-Through Penetration Resistance of a Spudcan on Sand Overlying Clay

This paper demonstrates the use of a geotechnical drum centrifuge in the calibration of a model to predict the peak punch-through penetration (qpeak) resistance of a spudcan on sand overlying clay. A series of loose sand overlying clay tests was performed and combined with an existing database of tests performed on dense sand overlying clay. The...

Wing flexibility effects in clap-and-fling

The work explores the use of time-resolved tomographic PIV measurements to study a flapping-wing model, the related vortex generation mechanisms and the effect of wing flexibility on the clap-and-fling movement in particular. An experimental setup is designed and realized in a water tank by use of a single wing model and a mirror plate to...

Modelling of turbulent jets and wall layers: Extensions of Lighthill's acoustic analogy with applications to computational aeroacoustics

Two extensions to Lighthill's aeroacoustic analogy are presented. First, equivalent sources due to initial conditions are derived that supplement those due to boundary conditions, as given by Ffowcs Williams & Hawkings. The resulting exact inhomogeneous wave equation is then reformulated with pressure rather than density as the wave variable,...