Ecostructure: Concrete design for improved marine biodiversity

In some parts of the world artificial marine structures now cover more than half of the available natural shoreline. Due to the impact of climate change and the need for improved coastal defences this number is set to increase, and these will inevitably have a significant impact on the local marine ecosystem. As an indicator of this impact, research in the UK has shown the epibiotic diversity to be significantly reduced on submerged artificial structures. The Ecostructure project is part funded by the Ireland Wales Cooperation Programme and has the objective of addressing climate change adaptation through ecologically sensitive coastal infrastructure. The approach under development is to increase the ecological value of artificial coastal infrastructure in the Irish Sea through careful design of pre–fabricated ecological engineering units.
A key parameter in the design of these units is material selection. Reinforced concrete plays an important role in the design of these units, due to its ease of production, relatively low cost and its suitability for mass construction. However when assessing concrete mixes for use in this application, a key issue is how easily the local marine organisms can colonise the hard concrete substrate. It is considered that key parameters can include binder composition, aggregate type, texture, colour etc. To assess these parameters, a testing programme has been developed that is focusing on 9 different concrete designs. These are assessed for key engineering parameters (strength, chloride diffusion coefficient etc.), as well their ecological colonisation performance. This is determined by placing concrete samples in marine environments in Ireland and measuring the ecological diversity through quadrat sampling at a number of time intervals. This testing is taking place in Dublin and initial results are presented.