合成水化硅酸钙(C-S-H)对水泥基材料Cl-结合性能的影响
Effect of Synthetic Calcium Silicate Hydrate(C-S-H)on Combination of Chloride Ions with Cementitious Materials
张余果 1孙丛涛 1张鹏 2孙明 3耿圆洁 4樊亮 3翟晓凡 3段继周3
作者信息
- 1. 青岛理工大学土木工程学院 青岛 266033;中国科学院海洋研究所海洋环境腐蚀与生物污损重点实验室 青岛 266071;崂山实验室海洋腐蚀与防护开放工作室 青岛 266237
- 2. 青岛理工大学土木工程学院 青岛 266033
- 3. 中国科学院海洋研究所海洋环境腐蚀与生物污损重点实验室 青岛 266071;崂山实验室海洋腐蚀与防护开放工作室 青岛 266237
- 4. 崂山实验室海洋腐蚀与防护开放工作室 青岛 266237;内蒙古科技大学土木工程学院 包头 014010
- 折叠
摘要
通过合成水化硅酸钙(C-S-H),研究了内掺C-S-H对水泥净浆Cl-结合性能的影响.采用XRD、TG-DTG、SEM以及EDS分析了水泥水化产物随龄期的物相演化和微观形貌变化.结果表明,净浆试件中自由Cl含量随龄期的增加皆呈先下降后上升的趋势.在龄期7、14和21d时,掺加C-S-H组净浆自由Cl-含量均大于未掺加C-S-H组,这是因为掺加的C-S-H粒径相对较大,比表面积相对较小,使得净浆中C-S-H总比表面积减小,降低了 C-S-H对Cl-的结合;其次,在水泥净浆中掺加C-S-H能够促进水泥水化,提高水化早期pH值,高pH值也不利于C-S-H对Cl-的吸附;再次,掺加C-S-H净浆水化早期无Friedel's盐生成,化学结合Cl-能力较弱.在龄期28 d时,掺加C-S-H组净浆中有Friedel's盐的生成,化学结合提高了 Cl-结合量,故两组净浆自由Cl-含量较为相近.由于28 d时掺加C-S-H组净浆中存在较多SiO2,易发生火山灰反应生成低钙硅比的C-S-H以及pH值降低影响Friedel's盐稳定性,使得35 d时自由Cl-含量上升明显.
Abstract
Mixtures of cement-based material with the addition of synthetic calcium silicate hydrated(C-S-H)was prepared,then the effect of internal admixture of C-S-H on the evolution of the combination ofchloride ions with the cement paste during aging process was investigated by means of XRD,TG-DTG,SEM and EDS.The results showed that the quantity of free chloride ions in the test pieces tended to decrease and then increase with aging process.At the ages of 7,14 and 21 d,the quantity of free chlo-ride ions in the cement paste with C-S-H was higher than that without C-S-H.This was due to the relative-ly larger particle size and smaller specific surface area of C-S-H,which reduced the total specific surface area of C-S-H in the cement paste and reduced the combination amount of C-S-H to chloride ions;in ad-dition,the addition of C-S-H to the cement paste could promote the hydration of cement and increase the pH value in the early hydration period,and the high pH value is not conducive to the adsorption of C-S-H on chloride ions;and there is no Friedel's salt generation in the early hydration period of the cement paste mixed with C-S-H,so that weaken the chemical combination ability for chloride ions.At the age of 28 d,Friedel's salt was generated in the cement paste with addition of C-S-H,thus the amount of chemi-cal combination of chloride ions increased,so the free chloride ion quantity of the two groups of cement paste was more similar.Due to more SiO2 existed in the cement paste with C-S-H at 28 d,the pozzolanic reaction to generate C-S-H with low Ca/Si and the decrease in pH value affecting Friedel's salt stability,the amount of free chloride ions increased significantly at 35 d.
关键词
水泥净浆/Cl-/水化硅酸钙/Cr结合/pH值Key words
cement paste/chloride ions/calcium silicate hydration/chloride binding/pH value引用本文复制引用
基金项目
山东省自然科学基金重点项目(ZR2020KE046)
国家重大科研仪器研制项目(41827805)
出版年
2024
NETL
NSTL
万方数据