強塑劑於高性能混凝土中之效能評估

The effective evaluation of superplasticizer in high performance concrete

陳慶宏(Chen Ching Hong)

指導教授 ： 許貫中

國立臺灣師範大學/理學院/化學系/碩士(1999年)

摘要

混凝土由於來源充足、價格低廉、污染性低及優越抗壓強度，因此成為結構工程上使用最多的材料，而強塑劑則是拌製混凝土高流動性的主要成份之一。
強塑劑的種類、分子量、添加劑量、拌和方式及添加時機均會影響其在水泥表面的吸附行為，進而影響新拌混凝土的工作性及硬固混凝土的機械性與耐久性，故強塑劑的了解與應用在混凝土科技上扮演相當重要的角色。
本論文乃針對幾種商業強塑劑(SNF、SMF、MLS、PCA、HP-70、SNF+PCA、HP-11R)，分析其基本性質、減水率及其添加對水泥(砂)漿流變性質之影響，進而決定不同配比下所需強塑劑的最佳劑量及影響最佳劑量各項因素之探討，並建立迴歸方程式以便迅速找出不同配比的混凝土之最佳劑量。
由實驗結果得知，這幾種強塑劑適量的添加於水泥(砂)漿中均有不錯的減水效果，而SNF、PCA、SNF+PCA之流動性維持較MLS、SMF佳，且藉由黏度計所測得的視黏度及屈服應力與馬緒流動錐所測得的流動時間及迷你坍度錐所測得的平均擴散直徑均可決定不同配比下強塑劑的最佳劑量。在相同配比下，以SMF及MLS所需最佳劑量較高，其他幾種則較低；水灰比愈高，所需最佳劑量愈低；添加飛灰、增加砂含量會使得最佳劑量提高；添加爐石則會降低最佳劑量；水泥、砂種類對最佳劑量亦有影響。最後，建立迴歸方程式以預測不同配比的混凝土所需強塑劑之最佳劑量。

關鍵字

強塑劑 ； 最佳劑量

並列摘要

Concrete is the material mostly used in construction engineering because of its availability in source, low cost, low pollution and excellent compressive strength. Superplasticizer (Sp) is one of the main components to make concrete with high fluidity.
It is reported that the type, molecular weight, dosage, mixing method and time of addition of Sps affect their adsorption behavior on cement particles, the workability of fresh concrete, and the mechanical properties and durability of hardened concrete. Therefore, the understanding and application of Sps are important on the concrete technology.
This thesis has evaluated the basic properties and water-reduction of 7 commercial Sps, namly SNF, SMF, MLS, PCA, SNF+PCA, HP-70 and HP-11R, studied the effect of Sps on the rheology properties of cement pastes or mortars, determined the optimal Sp dosage and finally correlated the optimal dosage for concrete with different mix proportions by several correlation equations.
The tested results indicate that all Sps exhibit good water-reduction effects. Both SMF and MLS show worse fluidity retention than the others. The optimal dosage of Sps was determined from the measured apparent viscosity, yield stress, Marsh cone flow time and mini-slump for various mix proportions. The optimal dosage of both SMF and MLS is higher than the others; the optimal dosage of all Sps increases with decreasing w/c ratio and increasing sand content；It also increases as fly ash replacement is increased or slag replacement is decreased. Different type of cement and sand show different effects on the optimal dosage. Finally, correlation equation were established to correlate the experimental values.

並列關鍵字

superplasticizer ； optimal dosage

參考文獻

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