摘要
用超细石灰石通过煅烧对粉煤灰进行表面改性,使粉煤灰表面生成具有活性的硅酸盐矿物,增加参与早期水化的胶凝材料量,从而提高粉煤灰的活性。采用扫描电子显微镜(SEM)和X射线衍射(XRD)等现代分析方法对改性粉煤灰样品进行表征,并且对掺改性粉煤灰水泥浆体进行强度和体积变形试验。研究结果表明:改性粉煤灰表面生成了钙黄长石等钙铝硅酸盐;与掺未改性粉煤灰的水泥浆体相比,表面改性粉煤灰改善了粉煤灰与水泥浆体之间的界面结构,提高了掺表面改性粉煤灰水泥浆体的早期强度,并降低其干燥收缩;用30%石灰石进行改性的粉煤灰比用20%石灰石的改性效果好,单位强度干燥收缩小。
To increase the quantity of cementitious materials participating in early hydration and increase the activity of fly ashes,silicate minerals with activity were formed on the surface of fly ashes by calcining mixtures of fly ashes and superfine limestone.The samples of modified fly ashes were characterized by SEM and XRD.The strength and volume deformation of the cement pastes with surface-modified fly ashes were tested.The results show that,calcium aluminum silicate such as gehlenite were generated on the surface of modified fly ashes.Compared with cement pastes with unmodified fly ashes,surface-modified fly ashes enhance the early compressive strength and reduce drying shrinkage of cement pastes.The effect of surface-modified fly ash with 30% limestone are better then the one with 20% limestone,and drying shrinkages per MPa strength of cement pastes are little.
出处
《混凝土》
CAS
CSCD
北大核心
2010年第9期83-86,共4页
Concrete
基金
国家重点基础研究发展计划(2009CB623105)
关键词
粉煤灰
表面改性
抗压强度
干燥收缩
fly ash
surficial modification
compressive strength
drying shrinkage
