Dr Juliana Calabria Holley
BSc (Hons), MSc, PhD
Dr Juliana Calabria Holley is a Lecturer in the Department of Architecture and Civil Engineering. Her research area is in construction materials, specialising in micro and nanostructure of adobe and fired bricks, cementitious materials, surface engineering via sol-gel technology, adsorption process and porosity systems.
Juliana obtained her Architect diploma from Catholic University of Minas Gerais (1999), Brazil. She acted as a self-employed Architect from1999 until 2009 specialising in the residential sector. During this time she also obtained her master's from Federal University of Minas Gerais, (2004) Brazil and her PhD from Federal University of Minas Gerais, Brazil and Imperial College of London, United Kingdom (2008), both in the field of Materials Science and Engineering.
Her PhD research focused on developing breathable protective coatings for the sustainable and low-embodied energy material, adobe brick. The study approach was based on surface engineering strategies such as adsorption process and porosity systems. The interfacial modifications attained were the development of hydrophobic and bactericide nano membranes by means of sol gel process initially containing an inorganic precursor linked to organic molecules.
The mechanisms used to understand adobe degradation reactions were mirrored in clay surface reaction such as ion exchange reactions dependent on the ion concentration, hydration, pH, Zeta potential, and other ions. According to this research the sol-gel membranes stabilised the surface of the adobe samples by substituting some of the top layer ions by organic molecule groups.
Juliana joined the University of Bath as a Research Associate in March 2012 working on the FIBCEM project. FIBCEM is a project funded by the European Commission under the 7th Framework Programme. The full project title is: Nanotechnology Enhanced Extruded Fibre Reinforced Foam Cement Based Environmentally Friendly Sandwich Material for Building Applications. The FIBCEM Consortium consists of ten project partners from five different European countries (Spain, Italy, Lithuania, United Kingdom and Denmark).
Fibre reinforced cement (FRC) is a durable, fire and corrosion resistant material widely used in the construction industry. Coupled with the low cost of Portland cement, these properties make it ideally suited for applications such as roofing tiles and sidings. The FIBCEM material will consist of a cement-based sandwich composed of a foam cement core and fibre-reinforced cement skins. The foam core will be produced using a nano-scale foaming agent to ensure the formation of an optimum closed cell foam structure with a micro-scale cell size with a narrow cell size distribution. Both the foam and the skins will be reinforced with nano-clays to improve both the mechanical and transport properties of the material. The foam cement core will result in a lower density compared to existing FRC, whilst the reinforced skins will ensure the mechanical properties are improved. Added functionality in the form of decreased thermal conductivity and increased sound insulation properties will result from the foam core.
By using a foam core and replacing part of the cement with materials such as fly ash and silica fume, the CO2 footprint of the material will be significantly reduced compared to existing FRC.
Her main research interests lay with low carbon cement, natural building materials, surface engineering and modification and sol-gel technology applied to the built environment.