Binders with large portions of carbon-intensive Portland cement replaced by supplementary cementitious materials (e.g. fly ash) are more susceptible to carbonation mainly due to their lower CO₂ buffering capacity. This conclusion is usually drawn from accelerated experiments at elevated CO₂ levels involving processes that seriously differ from natural carbonation. The resulting presence of H₂O reactant in the pore system and the carbonated microstructure itself may be very different. In this paper, these phenomena were investigated for High-Volume Fly Ash (HVFA) mortar via carbonation tests at ±0.04% CO₂ (natural carbonation), 1% CO₂ and 10% CO₂. Internal humidity sensor monitoring and ¹H NMR relaxometry revealed the highest water vapour and liquid water contents after carbonation at 10% CO₂. Carbonation at 10% CO₂ results in a coarser pore structure than carbonation at 1% CO₂, and this probably due to a higher degree of C–S–H carbonation.

大部分碳密集型波特兰水泥的粘合剂被补充性胶凝材料（例如粉煤灰）替代的原因更易发生碳化，这主要是由于其较低的CO ₂缓冲能力。这个结论通常是从加速的实验中得出的，该实验是在升高的CO ₂水平下进行的，该过程涉及与天然碳酸化过程截然不同的过程。孔系统中产生的H ₂ O反应物的存在与碳酸化微结构本身可能有很大不同。在本文中，通过在±0.04％CO ₂（自然碳化），1％CO ₂和10％CO _2的碳化试验对高粉煤灰（HVFA）砂浆进行了研究。。内部湿度传感器监测和¹ H NMR弛豫法显示，在10％CO ₂碳化后，水蒸气和液态水含量最高。10％CO _2的碳酸化比1％CO _2的碳酸化导致的孔隙结构更粗糙，这可能是由于C–S–H碳酸化程度更高。