Carbonation Potential of Cementitious Structures in Service and Post-Demolition: A Review

Abstract

The construction sector is responsible for a great environmental impact. The cement industry, which is included in this sector, emits about 650 to 800 kg of CO2 per each tonne of cement produced, being one of the most polluting industries in terms of greenhouse gas emissions. The cement manufacturing process releases about 7% of the total worldwide CO2 emissions. However, concrete and cement-based materials present CO2 uptake potential during their service life and post-demolition through carbonation processes. The carbonation reactions rate depends on several factors, namely type and content of cement, porosity of concrete, temperature, relative humidity and exposure conditions area. Therefore, to estimate the CO2 capture of concrete during its life cycle is not a straightforward calculation. Some studies have been developed using different methodologies in order to evaluate the CO2 potential of cementitious elements in service and post-demolition. This paper reviews the documented approaches that quantify the CO2 uptake of concrete over time, summarizing the assumptions adopted for each previous work. Overall, it was concluded that part of the CO2 emissions released during cement production are reabsorbed by concrete products during their life cycle, which partially offsets the environmental impact and reduces the CO2 footprint of the cement industry.

Chemistry and pathways to net zero for sustainability

“…79,80 It should also be noted that concrete absorbs CO 2 from the atmosphere, partly offsetting the amount liberated in its production. 81…”

“…79,80 It should also be noted that concrete absorbs CO 2 from the atmosphere, partly offsetting the amount liberated in its production. 81 Steel is the most widely used metal in the world, traditionally produced from iron oxide ores by very energy-intensive reduction processes using coal or coke that liberate 1.8 tonnes CO 2 per tonne of steel, as a global average. In 2020, world production of 1.86 billion tons of steel contributed 7-9% of annual global anthropogenic carbon emissions.…”