Can low-carbon concrete technologies simultaneously reduce emissions and improve arid-climate structural integrity in Egypt?

Egypt is going through a period of rapid urban expansion, requiring enormous quantities of concrete to sustain. Yet, Ordinary Portland Cement (OPC) presents two significant problems. The first is environmental; OPC accounts for roughly 7-8% of global CO₂ emissions. The second is technical: in Egypt's hot desert climate, concrete is prone to plastic shrinkage cracking, thermal cracking, and sulphate attack, all of which compromise structural integrity over time. This literature review examines whether low-carbon concrete technologies can address both environmental and durability issues simultaneously.

Research conducted with peer-reviewed literature across Web of Science, Google Scholar and ScienceDirect showed five main low-carbon concrete formulations to be evaluated against Egyptian specific criteria: carbon reduction potential, early-age strength development, resistance to sulphate attack, curing requirements, and local material availability. The formulations compared include high-volume fly ash concrete, slag-blended concrete, limestone calcined clay cement (LC³), ternary blends with silica fume, and geopolymer concrete.

Findings declare that no single formulation is optimal for every situation. Rather, for general construction, LC³ appears the most promising. It relies on limestone and clay abundant in Egypt, achieves early-age strength comparable to OPC which aids mitigation of plastic shrinkage, and reduction of emissions by 30-40%. Slag-blended concrete is well-suited for aggressive environments like saline soils and coastal areas. This is due to its excellent sulphate resistance and availability from Egypt's steel industry. For signature structures requiring very high performance, ternary blends are appropriate, though their cost and imported materials limit them to premium applications. Geopolymers and fly ash concretes face significant challenges with availability and curing temperature sensitivity, making them practical only for precast elements.

The review concludes that low-carbon concrete can reduce emissions and improve structural integrity in Egypt, but success is dependent on formulation selection aligned with each practical requirement.