Evaluation of natural colonisation of cementitious materials: Effect of bioreceptivity and environmental conditions

Abstract

Incorporation of living organisms, such as photosynthetic organisms, on the structure envelope has become a priority in the area of architecture and construction due to aesthetical, economic and ecological advantages. Important research efforts are made to achieve further improvements, such as for the development of cementitious materials with an enhanced bioreceptivity to stimulate biological growth. Previously, the study of the bioreceptivity of cementitious materials has been carried out mainly under laboratory conditions although field-scale experiments may present different results.\ud \ud This work aims at analysing the colonisation of cementitious materials with different levels of bioreceptivity by placing them in three different environmental conditions. Specimens did not present visual colonisation, which indicates that environmental conditions have a greater impact than intrinsic properties of the material at this stage. Therefore, it appears that in addition to an optimized bioreceptivity of the concrete (i.e., composition, porosity and roughness), extra measures are indispensable for a rapid development of biological growth on concrete surfaces. An analysis of the colonisation in terms of genus and quantity of the most representative microorganisms found on the specimens for each location was carried out and related to weather conditions, such as monthly average temperature and total precipitation, and air quality in terms of NOx, SO2, CO and O3.\ud \ud OPC-based specimens presented a higher colonisation regarding both biodiversity and quantity. However, results obtained in a previous experimental programme under laboratory conditions suggested a higher suitability of Magnesium Phosphate Cement-based (MPC-based) specimens for algal growth. Consequently, carefully considering the environment and the relationships between the different organisms present in an environment is vital for successfully using a cementitious material as a substrate for biological growth.Peer ReviewedPostprint (author's final draft

Calcium Carbonate Precipitation by Bacillus and Sporosarcina Strains Isolated from Concrete and Analysis of the Bacterial Community of Concrete

“…The ability to exist in such an alkaline, high-salt environment is crucial for calcium carbonate-precipitating bacteria because concrete itself represents such environments [9,26]. Therefore, the three strains, Bacillus sp.…”

“…The parameters of a bacterial culture environment such as temperature and aeration can influence the types of calcium carbonate produced by CCP-capable bacteria [11,17,26]. Because all three strains were incubated under the same conditions, the different structure (shape) of the resulting precipitated crystals could be due to differences in their innate mechanisms of utilization of calcium.…”

Evaluation of microbial proliferation on cementitious materials exposed to biogas systems

“…Sa values were of the same order of magnitude for CEM I, CEM III and CAC surfaces (1.10-1.62 µm) but the value was much higher for CEM I-Ox ones (5 µm) ( Table 2). Some studies have investigated the impact of mortar surface roughness on fungal colonization [17,18] and have found the Sa parameter to be between several tens of nm and several tens of µm. However, surface texture was not characterized, notably through skewness or kurtosis.…”

Microbiome-Inspired Green Infrastructure (MIGI): A Bioscience Roadmap for Urban Ecosystem Health

“…Firstly, the calibration of pore size can enable water absorption and retention, reaching colonising organisms through capillary or surface-binding effects, and secondly as a means to exploit extrinsic factors for bioreceptivity through the collection of organic material and fixation of cryptogamic surface cover. Different compositions of bioreceptive cementitious materials have been explored based on Magnesium Phosphate Concrete (Manso et al, 2015) and other Ordinary Portland Concrete (OPC) mixes with the aim to create long-term carbon offset. Studies of OPC have shown that apart from altering the physico-chemical properties of materials, morphological variations explored via computational design strategies are a powerful means to reduce water run-off and increase moisture retention, extending the residence time to create zones for accelerated growth (Cruz, 2021).…”