- 期刊
探討水泥化性與減水劑對於水泥漿體流變行為影響之研究
The Effect of Cement Chemical Component and Type of Superplasticziers on Rheology Property of Cement Paste
摘要
水泥漿體流變特性會影響新拌混凝土工作度穩定性，而水泥中化學組成成分是造成水泥漿體流變行為產生變異的重要因素之一，尤其當新拌混凝土含有萘磺酸系的減水劑時，更容易因化學成分不匹配而造成新拌混凝土坍度損失現象。因此，本研究針對60組不同時間取樣生產的波特蘭I型水泥，利用0.3水灰比（w/c=0.3）探討水泥化性與不同種類減水藥劑對於水泥漿體坍流度損失的影響。試驗結果顯示，水泥化學成分中鈉、鉀、硫、鹼等因子均對於水泥漿體坍度損失率具正相關影響，萘磺酸系與羧酸系減水劑添加於相同化性成分水泥之中時，羧酸系減水劑組具有較大水泥漿體初始坍流度，約高於萘磺酸系減水劑組約10～15%，且90分鐘後水泥漿體坍流度損失率也較萘磺酸系組小，說明萘磺酸系減水劑較容易受水泥化性之影響。試驗結果也顯示當水泥加水與藥劑拌合並靜置90分鐘後水泥漿體坍流度損失小於20%時，水泥化學成分中鈉、鉀、硫值含量分別小於0.333%、0.784%、與2.23%。因此，當生產水泥時應管控原物料使用，有效降低水泥化學成分中鈉、鉀、硫含量應能改善新拌混凝土坍度損失現象，提升水泥材料於工程應用上的穩定性。
並列摘要
The rheological property of Portland cement affects the workability of fresh concrete. The cement chemical component is one of crucial effects on change rheological property of cement paste, especially on the fresh concrete made with polynaphthalene sulfonate superplasticizer (PNS). In this study, over 60 sampling Portland type I cement, and the cement paste made by w/c=0.3 were used to investigate on the cement chemical components/type of superplasticizers with slump loss of cement paste. Test result shows that the cement paste made with Polycarboxylate superplasticizer have higher fluidity during the first minutes and lower fluidity loss in 90 minutes than the cement paste made with polynaphthalene sulfonate superplasticizer. It indicates that the polynaphthalene sulfonate superplasticizer used in cement paste is lower compatibility, and the cement paste rheological property is high affected by cement chemical component. The fluidity loss increases with the increasing the content of sodium oxide, Potassium oxide, and sulfate oxide of cement. The optimum content of sodium oxide, Potassium oxide, and sulfate oxide for the fluidity loss within 20% in 90 minutes should be controlled lower than 0.333%, 0.784%, and 2.23%, respectively.