[[alternative]]Investigation of the basic properties of chemical admixtures and

[[abstract]]化學摻料為製備高性能混凝土的關鍵成分，本研究乃收集國內幾種商 用的化學摻料，如磺酸化荼甲醛聚合物（代號N1、N2、N3、N4）、磺酸化 三聚氰胺甲醛聚合物（M1）和實驗室所自行合成之磺酸化酚甲醛聚合物（ S1），由IR、UV、TGA、GPC來分析其基本化學特性。並製作添加不同摻料 及摻料添加量的水泥漿體，於1、3、7及28天齡期時，利用固態 29Si MAS NMR光譜技術，分析水泥漿體之水化程度和聚矽陰離子長度；應用X光粉末 繞射儀分析CH和C3S的含量；應用維卡針來分析凝結時間；據此探討摻料 對水泥水化作用之影響。另外亦由流度、抗壓強度和MIP孔隙度測試來研 究摻料對水泥漿體的材料性質。研究結果顯示不同種類的摻料有不同之外 觀、固含量、UV光譜圖和分子量大小。水泥漿體之水化程度均隨齡期增加 而增加，而聚矽陰離子長度與齡期亦成正比關係，且0.4水灰比漿體較0.3 者有更高的水化程度。當添加摻料時會抑制水泥漿體之水化作用，其中以 N2摻料影響最大、S1次之、其次為N1、而添加M1影響最小，並且在相同齡 期下，摻料添加量越多，則漿體之水化程度相對地越小。另外由水泥凝結 時間測試，可發現添加摻料會延長水泥之凝結時間，以添加N2摻料凝結時 間最長、S1次之、其次為N1、M1最短，而添加量越多，則其凝結時間也越 長。由漿體材料性質分析得添加摻料均會造成水泥粒子分散，增加漿體之 流動性，以及減少孔隙體積，使試體較緻密，因此增加其抗壓強度，但若 添加了會嚴重抑制水化的摻料，如N2和S1則會因水化程度不夠，導致試體 抗壓強度較弱。 Chemical admixture is one key component in forming high performance concrete. This study has selected several domestic chemical admixtures, namely sulfonated naphthalene- formaldehyde condensates (N1, N2, N3, N4), sulfonated melamine- formaldehyde condensates (M1), and sulfonated phenolic resin (S1). The basic properties of these chemical admixtures were determined through IR, UV, TGA and GPC measurements. The cement pastes with or without chemical admixtures present were prepared and tested at the curing age of 1, 3, 7, 28day. The degree of hydration and the length of polysilicate of tested materials were analyzed from Solid 29Si MAS NMR spectra; the amount of CH and C3S of samples were examined by using a powder X-ray diffractometer; the Vicat Needle was applied to determine the setting time of cement pastes. Thus, the effects of admixtures on the hydration behavior of cement pastes were investigated. Moreover, the effect of admixtures on the material properties of harden samples were also examined through fluidity, compressive strength and porosity measurements. The results show that different type of admixture presents different properties such as appearance, solid content, UV spectrum and molecular weight and distribution. Both the degree of hydration and the length of polysilicate of cement pastes increases with curing age. Pastes with W/C=0.4 become more hydrated than those with W/C=0.3. Admixtures would lower the degree of cement hydration or prolong the setting time; the retarding effect is in the order of N2 >S1 >N1 > M1. Besides, increase of admixture dosage also show more retarding effect. As most chemical admixtures could enhance the dispersion of cement particles; they will enhance the fluidity of cement pastes, densify the microstructures, and increase the compressive strength of the resulting materials. However, it is noted that both N2 and S1 exhibit less reinforcement effect, since they show more retarding effect on the cement hydration. Chemical admixture is one key component in forming high