FDN减水剂对建筑石膏水化和硬化体结构的影响

Influence of FDN Superplasticizer on the Hydration Process and Microstructure of Hardened Building Gypsum Paste

采用SEM扫描电镜、氮吸附法和MIP压汞测孔技术,水化温度、水化率和电导率等测试手段,研究了萘系减水剂FDN对建筑石膏水化进程及其硬化体强度、孔结构、晶体形貌的影响.结果表明:FDN可显著提高建筑石膏硬化体强度,当FDN掺量在1.0%(质量分数)以内时,建筑石膏硬化体强度增长较快;FDN对建筑石膏水化进程、水化产物形貌影响甚微,但可明显改善硬化体孔结构,使其孔隙率降低、孔径细化,而这正是减水剂增加建筑石膏硬化体强度的原因所在.

By using measurement techniques such as scanning electric microscope（SEM）, mercury intrusion porosimetry（MIP）, nitrogen adsorption porosimetry, hydration temperature test, hydration ratio test, and electric conductivity test et al, the influence of naphthalene-type（FDN） superplasticizer on th gypsum was inv e hydration process, strength, pore structure, and crystal morphology of building estigated. The results indicate that the addition of FDN increases the strength of building gypsum significantly. When its dosage is below 1% mass ratio, the strength of building gypsum is rapidly increased as a function of superplasticizer addition. FDN superplasticizer has a minor effect on the crystal morphology of hydration products, but it could improve the pore structure of hardened gypsum paste markedly, leading to the decrease of porosity and average pore size, which is the very reason that superplasticizers reinforce building gypsum.