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Project

Pore-scale modelling of the impact of water repellent agents on the hygric properties of building materials

More and more frequently, the application of a water repellent agent is considered to safeguard existing and new facades from moisture damage. The positive impact of that measure can however only be ensured by carefully tuning the agent to the building material and moisture exposure. That tuning is possible via hygrothermal simulations, wherein the hygric properties of the treated mate-rial layers are a crucial factor.Experimental determination of the properties for a spectrum of potential water repellent agents quickly becomes inhibitive however. This research proposal thus aims at characterising the impacts of water repellent agents on the hygric properties of building materials through pore-scale modelling. After identification of the untreated and treated pore systems, respectively demonstrating full or restricted capillary activity, a pore network model can be applied to quantify the moisture storage and transport properties of the hydrophobized materials. To attain these goals, research on four fronts will be performed: 1) hygric property characterisation of hydrophobised building materials to obtain their moisture storage and moisture transport properties for a range of building materials and water repellent agents;2) identification of the pores wherein the water repellent agent has (not) penetrated, using moisture stora-ge, nuclear magnetic resonance, and focused ion beam-scan¬ning electron microscopy measurements; 3) characterization of the influences of the water repellent agents on water-surface adhesion, via contact angle measurements, atomic force microscopy, and tests on microcapillaries;4) quantification of moisture storage and transport properties of hydrophobised materials through pore-scale modelling, and validation versus measured properties of hydrophobized materials;A final task is to demonstrate the tuning of hydrophobisation:5) proof-of-concept for the tuning of the water repellent agent towards the assembly under consideration, via hygrothermal simulations of hydrophobised massive facades with interior insulation;These activities build upon past and ongoing research of this group on both pore-scale modelling and water re-pellent agents, and hence are solidly founded on the current expertise of the research group.Completion of this project will bring advances to both scientific knowledge and industrial application: on the one hand it will strongly improve our insights on the hygric behaviour of porous materials and on the other hand it will highly enhance the reliability of water repellent agents in preserving our built environment.
Date:1 Oct 2018 →  Today
Keywords:porous building materials, hygric properties, water repellent agents, pore-scale modelling, hydrophobisation
Disciplines:Structural engineering, Other civil and building engineering