Carbon dioxide emissions from traditional and modified concrete. A review

The concrete industry is among the most significant contributors of carbon dioxide emissions into the atmosphere. Since this industry generates such a negative environmental impact, finding different ways to reduce the severe effect of concrete production without diminishing its excellent performance is mandatory. The partial replacement of cement with either organic or inorganic substances becomes an ecological method of managing large quantities of industrial and agricultural waste. Previously, several reviews have reported the mechanical and thermal properties of modified concrete; however, the effect of incorporating different industrial wastes on carbon dioxide emissions has yet to be considered. Thus, this article presents a comprehensive review of studies published between 2000 and 2023 where the carbon dioxide emissions in traditional and modified concrete samples were assessed. According the data founded CO₂ emissions are mainly affected by two aspects that are water/cement ratio and the substitution percentage. CO₂ emissions showed a trend of decreasing with increasing the water/cement ratio and decreasing with the increasing the percentage of substitution. Furthermore, carbon dioxide emissions depend on the type of substitute material. A substitute material with a lower emission factor has higher carbon dioxide emissions. Likewise, perspectives on this topic and other challenges facing the concrete industry are also discussed. It is expected that this review will motivate future studies to include calculations and assessments of carbon emissions as a parameter to quantify the environmental impact in the concrete industry.