Abstract Scanning electron microscopy was used to evaluate the porosity patterns found in microconcrete materials to better understand the gaseous diffusion pathways and reaction of CO2 within the bulk cement paste and interfacial transition zone (ITZ) of microconcrete materials containing different fly ash replacement types. Image segmentation was applied to evaluate the porosity as a function of distance from an exposed surface in the bulk cement paste and from aggregate boundaries in the ITZ in both carbonated and non‑carbonated microconcrete materials. The ITZ region remained more porous compared to the bulk cement paste for all microconcrete types after carbonation despite a change in the porosity profile across the ITZ region. Results indicate that both the carbonation reaction capacity and porosity before carbonation impact the decrease in porosity observed as a result of carbonation in the ITZ and bulk cement paste regions.

中文翻译：

---

碳化对粉煤灰置换微混凝土材料体积和 ITZ 孔隙率的影响

摘要 扫描电子显微镜用于评估在微混凝土材料中发现的孔隙率模式，以更好地了解二氧化碳在散装水泥浆和含有不同粉煤灰置换类型的微混凝土材料的界面过渡区 (ITZ) 内的气体扩散途径和反应。应用图像分割来评估孔隙率，该孔隙率是与散装水泥浆体中暴露表面的距离以及与碳酸化和非碳酸化微混凝土材料中 ITZ 中集料边界的距离的函数。尽管整个 ITZ 区域的孔隙率分布发生了变化，但在碳化后，与所有微混凝土类型的散装水泥浆相比，ITZ 区域的孔隙率仍然更高。