【摘要】：高效減水劑是制備高性能混凝土所必須的外加劑,已成為混凝土中第五種重要組分。目前,人們多采用δ-電位、減水劑吸附層厚度及吸附量來表征減水劑對水泥的作用效果。但未對拌合前的粉體材料物性進行研究。粉體表面能是粉體材料性能的重要參數(shù),因此,研究粉體表面物性對減水劑吸附的影響具有重要意義。本文通過對水泥、粉煤灰粉體表面能的測定,不同濃度的聚羧酸和萘系高效減水劑溶液中水泥、粉煤灰表面δ-電位的測定以及對高效減水劑的吸附量的測定,探討粉體表面能、粉體顆粒表面δ-電位與高效減水劑吸附量之間的關系。通過實驗主要得到以下研究結果:1.水泥粉體A、B、C的細度依次為:水泥A水泥B水泥C。隨著粉體細度的增加,去離子水與水泥粉體薄層之間的動態(tài)接觸角減小,親水性增強;水泥粉體的表面能也隨之增加。水泥粉體A、B、C的表面能依次為:55.5427mN·m-1、53.3935mN·m-1、50.5843mN·m-1。粉煤灰FA、FB的表面能依次為:42.9175mN·m-1和36.8512mN·m-1。粉體越細,表面能越大。當水泥粉體與粉煤灰的粒度分布相近時,水泥粉體的親水性大于粉煤灰的親水性,水泥粉體的表面能約為粉煤灰的1.33倍。2.在去離子水中,水泥顆粒最初表面δ-電位為正值,隨著水化時間的延長,δ-電位由正變負;而粉煤灰表面δ-電位為負值,且?guī)缀醪浑S時間變化。3.同種減水劑溶液中,水泥顆粒表面δ-電位隨初始濃度的增加而呈現(xiàn)上升的趨勢;隨時間的延長而降低。水泥顆粒在萘系高效減水劑中的δ-電位明顯高于在聚羧酸高效減水劑中。水泥水化時間越長,對減水劑吸附量越大。與聚羧酸高效減水劑相比,水泥顆粒在萘系高效減水劑溶液中表面出較高的吸附量,這與減水劑分子中所含作用基團和分子結構有關。而對于同種同濃度的減水劑溶液,吸附量由低到高依次為水泥A、水泥B、水泥C,即表面能越高,相應的吸附量也隨之增加。粉煤灰與水泥表現(xiàn)出類似的規(guī)律,但在不同程度上低于水泥的δ-電位、吸附量。4.在不同種類的高效減水劑溶液中,水泥和粉煤灰顆粒表面δ-電位絕對值和吸附量均隨減水劑初始濃度的增加而增大。且隨表面能的增大而增加,幾乎呈線性關系。
[Abstract]:The superplasticizer is a necessary admixture for the preparation of high performance concrete and has become the fifth important component in concrete. At present, 未-potential, adsorption layer thickness and adsorption amount are used to characterize the effect of water reducer on cement. But the physical properties of powder before mixing were not studied. The surface energy of powder is an important parameter of powder material properties. Therefore, it is of great significance to study the effect of surface physical properties of powder on the adsorption of water reducer. In this paper, the surface energy of cement, fly ash powder, cement with different concentrations of polycarboxylic acid and naphthalene superplasticizer solution, and the surface 未-potential of fly ash as well as the adsorption capacity of superplasticizer are studied. The relationship between 未-potential and adsorption capacity of superplasticizer on the surface of powder particles. The following results are obtained from the experiment: 1: 1. The order of fineness of cement powder A cement B cement C is: cement A cement B cement C. With the increase of powder fineness, the dynamic contact angle between deionized water and cement powder thin layer decreases, the hydrophilicity increases, and the surface energy of cement powder increases. The surface energy of the cement powder AZB C is 55.5427mN m-1and 53.3935mN m-1N m -1 50.5843mN m -1, respectively. The surface energy of the cement powder is 55.5427mN m -1 and 53.3935mN m -1 respectively. The surface energy of fly ash Fab is: 42.9175mNm-1 and 36.8512mN m-1respectively. The finer the powder, the greater the surface energy. When the particle size distribution of cement powder and fly ash is similar, the hydrophilicity of cement powder is greater than that of fly ash, and the surface energy of cement powder is about 1.33 times that of fly ash. In deionized water, the initial surface 未-potential of cement particles is positive, with the increase of hydration time, 未-potential changes from positive to negative, while that of fly ash is negative and almost does not change with time. In the same superplasticizer solution, the surface 未-potential of cement particles increases with the increase of initial concentration and decreases with the prolongation of time. The 未-potential of cement particles in naphthalene superplasticizer is significantly higher than that in polycarboxylic acid superplasticizer. The longer the hydration time of cement, the larger the adsorption amount of water reducer. Compared with polycarboxylic acid superplasticizer, the surface adsorption of cement particles in naphthalene superplasticizer solution is higher than that of polycarboxylic acid superplasticizer, which is related to the functional group and molecular structure of the superplasticizer molecule. For the same water reducer solution of the same concentration, the adsorption capacity increases with the increase of surface energy of cement A, cement B and cement C from low to high. Fly ash and cement show similar law, but lower than the 未-potential of cement, adsorption capacity. 4. In different kinds of superplasticizer solutions, the absolute value of 未-potential and adsorption capacity on the surface of cement and fly ash particles increase with the increase of initial concentration of water reducer. And it increases with the increase of surface energy, almost linearly.
【學位授予單位】：濟南大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ172.1;TU528.042.2

【參考文獻】

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1 崔正剛,B.P.Binks,J.H.Clint;薄層毛細滲透技術測定多孔性固體顆粒的表面能成分[J];日用化學工業(yè);2004年04期

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本文編號：2182595