Using mineral admixtures as cement replacement substance in concrete tends to increase in the future to provide greater sustainability in the construction industry. This paper aimed to study the influence of adding silica fume and fly ash as a weight of cement replacement on settlement cracking intensity of plastic concrete. Fifty-six mixtures were cast to evaluate the purpose of this study. Two types of cement (Portland cement and sulfate resistance cement) and two types of aggregates (dolomite and gravel) were considered. The cement was partially replaced by different ratios of silica fume (3%, 6%, 8%, and 10%) and different ratios of fly ash (10%, 15%, 20%, and 25%) of cement weight. In all concrete mixtures, a water-to-cementitious content ratio (w/cm) was 0.42. The results exhibited that the cracking intensity of settlement decreased as the slump decreased. Adding silica fume to the concrete significantly reduced the rate of appearance of settlement cracks. The ideal ratio for adding silica fume to the concrete mix was 8% from cement weight. Adding fly ash to mixtures did not significantly affect settlement cracking intensity, but enhanced the workability of fresh concrete.

中文翻译：

---

硅粉和粉煤灰对塑性混凝土沉降开裂强度的影响

使用矿物外加剂作为混凝土中的水泥替代物质在未来趋于增加，以在建筑行业提供更大的可持续性。本文旨在研究添加硅粉和粉煤灰作为水泥替代物的重量对塑性混凝土沉降开裂强度的影响。浇铸了 56 种混合物以评估本研究的目的。考虑了两种水泥（波特兰水泥和抗硫酸盐水泥）和两种骨料（白云石和砾石）。水泥被不同比例的硅粉（3%、6%、8% 和 10%）和不同比例的粉煤灰（10%、15%、20% 和 25%）代替水泥重量。在所有混凝土混合物中，水与水泥的含量比 (w/cm) 为 0.42。结果表明，随着坍落度的降低，沉降的开裂强度降低。在混凝土中添加硅粉可显着降低沉降裂缝的出现率。向混凝土混合物中添加硅粉的理想比例是水泥重量的 8%。在混合物中加入粉煤灰对沉降开裂强度没有显着影响，但提高了新拌混凝土的和易性。