The significant increase in carbon dioxide emissions caused by the construction industry is detrimental to our planet. This is rapidly increasing with the urbanization of cities that is gradually taking its toll on the available green spaces, which help in balancing such emissions. Recently, researchers have been trying to make use of bio-receptivity to create biomaterial systems that could be spread on building envelopes and support the growth of small plant species and microorganisms to establish on. Out of those materials, comes the concrete as a promising material for bio-colonization.
Within this context, this study aims at investigating the applicability of using bio-receptive concrete for building facades through the incorporation of living organisms like moss utilizing various compositions of concrete mixtures.
To meet this objective, moss samples were collected from different locations in Egypt and propagated using in-vitro moss propagation method to test their survivability under optimal growing conditions. Moreover, various concrete mixtures were conducted, incorporating Ground Granulated Blast Furnace Slag (GGBS) at 70% replacement level for Ordinary Portland Cement along with different types of lightweight aggregates examined under four different surface morphologies. The concrete produced was assessed for its fresh and hardened concrete properties. The resulting concrete’s hydraulic and chemical properties were also assessed through tests including pH value, total porosity, capillary water retention and capillary water content. As for the bio-receptivity examination, it was carried out through a static laboratory setup where concrete samples were initially inoculated, stored horizontally and regularly wetted via spraying. Images of samples were taken throughout a period of 8 weeks to record the progression of biological growth. Moreover, FESEM was conducted to examine the pore structure of some concrete mixtures.
It is observed that concrete incorporating light weight aggregates have higher workability, significantly better hydraulic properties (P<0.0001) and less unit weight compared to conventional concrete making it suitable for use in construction applications of light weight concrete as well as bio receptive applications on roofs and on walling facades. Additionally, the incorporation of GGBS at 70% replacement level seems to have no significant effect on increasing biofilm formation (P=0.1226). Results showed that surface morphology plays a significant role in the bio receptivity of concrete, on its own, independent of the material chemistry, pH and porosity (P<0.0001). All the results indicate that concrete mixtures have the ability to be modified in order to support and enhance natural vegetation on their surfaces.
This work results in better understanding of the properties of bio-receptive concrete that will not only help in greening building envelopes, but will also open the door for creating other sustainable solutions that help in balancing the Greenhouse Gas emissions (GHG) worldwide.
School of Sciences and Engineering
Construction Engineering Department
MS in Construction Engineering
Mohamed Nagib Abou-Zeid
Committee Member 1
Committee Member 2
Committee Member 3
Institutional Review Board (IRB) Approval
Approval has been obtained for this item
(2024).Applicability of Using Bio-Receptive Concrete For Building Facades in Egypt [Master's Thesis, the American University in Cairo]. AUC Knowledge Fountain.
Roupheil, Gina. Applicability of Using Bio-Receptive Concrete For Building Facades in Egypt. 2024. American University in Cairo, Master's Thesis. AUC Knowledge Fountain.