Recent developments in Low-Carbon Engineered Cementitious Composites (ECC)

The use of ultra-fine aggregate and high cementitious material dosage in ECC increases carbon emissions and causes serious environmental problems. Therefore, this review summarizes the low-carbon development of ECC in terms of the low-carbon raw material selection, durability improvement and carbonation curing for CO₂ utilization. Using green cementitious material, green aggregate, green fiber to instead of cement, river sand/silica sand, PE/PVA fiber can greatly reduce carbon emissions. However, the current carbon emissions assessment indicator of cement-based materials focuses on the preparation stage, lacking a unified standard for the life cycle. The good durability and self-healing properties of ECC contribute to service life and reduce carbon emissions, however, lacking a comprehensive durability failure study including fiber degradation, fiber-matrix interface weakness and matrix failure in ECC. The carbonation curing provides a viable method for sequestering a portion of the CO₂ emitted during cement production. And carbonation efficiency is influenced by raw material compositions such as alkaline industrial by-products, the interaction between mineral ions and fiber, and external environmental conditions (CO₂ concentration, humidity, and temperature). The alkaline mineral ions (Ca²⁺, Al³⁺, Mg²⁺, etc.) in raw material promote the carbonization reaction, but the current study on the interaction between mineral ions and fiber is insufficient, the optimal CO₂ concentration, humidity, and temperature can promote carbonation reaction, but the excessive levels will decrease CO₂ solubility and carbonation efficiency. This review reveals the low-carbon potential of ECC and clarifies the factors affecting carbonization reaction, offering valuable insights for the design of low-carbon ECC.