凝灰岩石粉和VF防裂剂对水泥基材料收缩性能的影响
发布时间：2018-11-24 08:50
【摘要】：为了探究不同掺量的凝灰岩石粉、VF防裂剂对水泥浆体收缩性能的影响及机理,测定了不同凝灰岩石粉和VF防裂剂掺量的化学收缩和干燥收缩,采用X射线衍射技术(XRD)研究不同龄期的复合水泥浆体水化产物,并采用压汞法(MIP)研究其孔结构。结果表明:凝灰岩石粉早期不参与水化,等量取代水泥后通过减少水泥熟料数量减少水泥浆体的化学收缩,并能填充较大孔隙,增大水泥浆体中较小毛细孔(孔径50 nm以下)所占的比例,使水泥基材料干缩变大;VF防裂剂中的明矾石和石膏与水泥水化过程中析出的Ca(OH)2反应生成膨胀性钙矾石补偿收缩,并填充较小孔隙,减少浆体中较小毛细孔所占的比例,从而减小干缩。凝灰岩石粉中活性成分在VF防裂剂的化学激发下二次反应加剧,复掺石粉和防裂剂的水泥浆体的化学收缩显著减少,生成的水化产物填充孔隙,明显的抑制石粉对浆体干燥收缩的增大效应。
[Abstract]:In order to investigate the effect and mechanism of VF anticracking agent on shrinkage of cement paste with different amount of tuff powder, the chemical shrinkage and dry shrinkage of different amount of tuff powder and VF anticracking agent were determined. The hydration products of composite cement paste at different ages were studied by X-ray diffraction (XRD) and the pore structure was studied by (MIP). The results show that tuff powder does not participate in hydration at the early stage, and the chemical shrinkage of cement paste can be reduced by reducing the quantity of cement clinker, and the larger pores can be filled after the same amount of cement is replaced. By increasing the proportion of smaller pores (pore size less than 50 nm) in cement paste, the dry shrinkage of cement-based materials becomes larger. Alunite and gypsum in VF anti-cracking agent react with Ca (OH) _ 2 precipitated during hydration of cement to form expansive ettringite to compensate shrinkage and fill in smaller pores to reduce the proportion of smaller capillary pores in slurry and thus reduce dry shrinkage. The secondary reaction of the active components in the tuff powder increased under the chemical excitation of the VF anti-cracking agent, the chemical shrinkage of the cement paste mixed with the stone powder and the anti-cracking agent decreased significantly, and the hydration products filled the pores. The increasing effect of stone powder on drying shrinkage of slurry was obviously inhibited.
【作者单位】： 河海大学力学与材料学院;水资源高效利用与工程安全国家工程研究中心;
【基金】：国家科技支撑计划资助(2015BAB07B04) 中央高校业务费(2016B04514)
【分类号】：TU528
本文编号：2353030
[Abstract]:In order to investigate the effect and mechanism of VF anticracking agent on shrinkage of cement paste with different amount of tuff powder, the chemical shrinkage and dry shrinkage of different amount of tuff powder and VF anticracking agent were determined. The hydration products of composite cement paste at different ages were studied by X-ray diffraction (XRD) and the pore structure was studied by (MIP). The results show that tuff powder does not participate in hydration at the early stage, and the chemical shrinkage of cement paste can be reduced by reducing the quantity of cement clinker, and the larger pores can be filled after the same amount of cement is replaced. By increasing the proportion of smaller pores (pore size less than 50 nm) in cement paste, the dry shrinkage of cement-based materials becomes larger. Alunite and gypsum in VF anti-cracking agent react with Ca (OH) _ 2 precipitated during hydration of cement to form expansive ettringite to compensate shrinkage and fill in smaller pores to reduce the proportion of smaller capillary pores in slurry and thus reduce dry shrinkage. The secondary reaction of the active components in the tuff powder increased under the chemical excitation of the VF anti-cracking agent, the chemical shrinkage of the cement paste mixed with the stone powder and the anti-cracking agent decreased significantly, and the hydration products filled the pores. The increasing effect of stone powder on drying shrinkage of slurry was obviously inhibited.
【作者单位】： 河海大学力学与材料学院;水资源高效利用与工程安全国家工程研究中心;
【基金】：国家科技支撑计划资助(2015BAB07B04) 中央高校业务费(2016B04514)
【分类号】：TU528
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