Towards a low CO2 emission building material employing bacterial metabolism (2/2): Prospects for global warming potential reduction in the concrete industry

Abstract

The production of concrete is one of the most significant contributors to global greenhouse gas emissions. This work focuses on bio-cementation-based products and their potential to reduce global warming potential (GWP). In particular, we address a proposed bio-cementation method employing bacterial metabolism in a two-step process of limestone dissolution and recrystallisation (BioZEment). A scenario-based techno-economic analysis (TEA) is combined with a life cycle assessment (LCA), a market model and a literature review of consumers’ willingness to pay, to compute the expected reduction of global GWP. Based on the LCA, the GWP of 1 ton of BioZEment is found to be 70–83% lower than conventional concrete. In the TEA, three scenarios are investigated: brick, precast and onsite production. The results indicate that brick production may be the easiest way to implement the products, but that due to high cost, the impact on global GWP will be marginal. For precast production the expected 10% higher material cost of BioZEment only produces a marginal increase in total cost. Thus, precast production has the potential to reduce global GWP from concrete production by 0–20%. Significant technological hurdles remain before BioZEment-based products can be used in onsite construction scenarios, but in this scenario, the potential GWP reduction ranges from 1 to 26%. While the potential to reduce global GWP is substantial, significant efforts need to be made both in regard to public acceptance and production methods for this potential to be unlocked.

Transformation of Construction Cement to a Self-Healing Hybrid Binder

“…Within the cement, and especially on its surface, Ca(OH) 2 under consumption of CO 2 is converted to CaCO 3 and H 2 O [19]. This reaction from soluble Ca(OH) 2 leaching out from the cement into the crack to solid CaCO 3 is accelerated by bacteria present in the cement, which supply metabolic Ca 2+ ions from their nutrients, such as calcium propionate Ca(C 3 H 5 CO 2 ) 2 .…”

Opportunities and challenges for engineering construction materials as carbon sinks

“…Several biological mechanisms have been explored to support carbon-sequestration in concrete. These have included microbial-and fungal-driven pathways to produce CaCO3 as bio-cementation routes for reduced GHG emissions [52][53][54]. There are a variety of methods to produce such bio-cements, and depending on feedstocks, it has been proposed that these cements could lead to a reduction in GHG emissions of more than 70% relative to Portland cement [53].…”

“…These have included microbial-and fungal-driven pathways to produce CaCO3 as bio-cementation routes for reduced GHG emissions [52][53][54]. There are a variety of methods to produce such bio-cements, and depending on feedstocks, it has been proposed that these cements could lead to a reduction in GHG emissions of more than 70% relative to Portland cement [53]. Distinct from a mineralization process, plant biomass has been proposed as an alternative to mineral aggregates, where photosynthesis during cultivation could contribute to carbon-fixing [55,56] and can lower the embodied energy of the concrete [57].…”

Bioprecipitation of calcium carbonate mediated by ureolysis: A review

“…The certainly has the potential to penetrate the commercial market because it can be used to produce construction materials using low temperature and renewable energy sources [102].…”