水泥材料表面物性对高效减水剂吸附的影响研究
发布时间：2018-08-14 10:39
【摘要】：高效减水剂是制备高性能混凝土所必须的外加剂,已成为混凝土中第五种重要组分。目前,人们多采用δ-电位、减水剂吸附层厚度及吸附量来表征减水剂对水泥的作用效果。但未对拌合前的粉体材料物性进行研究。粉体表面能是粉体材料性能的重要参数,因此,研究粉体表面物性对减水剂吸附的影响具有重要意义。本文通过对水泥、粉煤灰粉体表面能的测定,不同浓度的聚羧酸和萘系高效减水剂溶液中水泥、粉煤灰表面δ-电位的测定以及对高效减水剂的吸附量的测定,探讨粉体表面能、粉体颗粒表面δ-电位与高效减水剂吸附量之间的关系。通过实验主要得到以下研究结果:1.水泥粉体A、B、C的细度依次为:水泥A水泥B水泥C。随着粉体细度的增加,去离子水与水泥粉体薄层之间的动态接触角减小,亲水性增强;水泥粉体的表面能也随之增加。水泥粉体A、B、C的表面能依次为:55.5427mN·m-1、53.3935mN·m-1、50.5843mN·m-1。粉煤灰FA、FB的表面能依次为:42.9175mN·m-1和36.8512mN·m-1。粉体越细,表面能越大。当水泥粉体与粉煤灰的粒度分布相近时,水泥粉体的亲水性大于粉煤灰的亲水性,水泥粉体的表面能约为粉煤灰的1.33倍。2.在去离子水中,水泥颗粒最初表面δ-电位为正值,随着水化时间的延长,δ-电位由正变负;而粉煤灰表面δ-电位为负值,且几乎不随时间变化。3.同种减水剂溶液中,水泥颗粒表面δ-电位随初始浓度的增加而呈现上升的趋势;随时间的延长而降低。水泥颗粒在萘系高效减水剂中的δ-电位明显高于在聚羧酸高效减水剂中。水泥水化时间越长,对减水剂吸附量越大。与聚羧酸高效减水剂相比,水泥颗粒在萘系高效减水剂溶液中表面出较高的吸附量,这与减水剂分子中所含作用基团和分子结构有关。而对于同种同浓度的减水剂溶液,吸附量由低到高依次为水泥A、水泥B、水泥C,即表面能越高,相应的吸附量也随之增加。粉煤灰与水泥表现出类似的规律,但在不同程度上低于水泥的δ-电位、吸附量。4.在不同种类的高效减水剂溶液中,水泥和粉煤灰颗粒表面δ-电位绝对值和吸附量均随减水剂初始浓度的增加而增大。且随表面能的增大而增加,几乎呈线性关系。
[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.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ172.1;TU528.042.2
本文编号：2182595
[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.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ172.1;TU528.042.2
【参考文献】
相关期刊论文 前1条
1 崔正刚,B.P.Binks,J.H.Clint;薄层毛细渗透技术测定多孔性固体颗粒的表面能成分[J];日用化学工业;2004年04期
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