摘要
制备了钙矾石(AFt)、单硫型硫铝酸钙(AFm)和钾长石类单矿物,并研究了三聚氰胺磺酸盐甲醛缩聚物(PMS)、β-萘磺酸盐甲醛缩合物(BNS)及聚羧酸盐(PC)等几种化学成分不同的超塑化剂在其早期水化颗粒表面上的吸附行为.研究发现,zeta电位是决定水泥颗粒表面对超塑化剂吸附量的关键因素.以溶液沉淀析出法人工合成的AFt具有较高的正zeta电位,能吸附大量带负电荷的超塑化剂,AFm仅带少量正电荷,其吸附超塑化剂相对较少,钾长石、氢氧钙石和石膏的zeta电位几乎为零或负值,因而基本不吸附超塑化剂.根据实验结果,笔者认为水化水泥颗粒用马赛克结构表示为最佳,而超塑化剂主要吸附在AF表面上.
The adsorption behaviour of chemically different superplasticizers, such as melamine formaldehyde sulphite polycondensate（PMS）, β-naphthalene sulfonate formaldehyde polycondensate（BNS） and polycarboxylate（PC）, on early hydrating cement phases was studied. For this purpose, pure ettringite（AFt）, monosulfate（AFm） and syngenite were prepared. The adsorbed amount and zeta potential of early hydration products were measured. It is found that zeta potential is the key factor determining the amount of superplasticizer absorbed. Synthetic ettringite precipitated from solution shows a highly positive zeta potential, hence it adsorbs great amount of negatively charged superplasticizer. Monosulfate has only a slightly positive zeta potential and adsorbs smaller amounts of superplasticizer. For syngenite, portlandite and gypsum, the zeta potential is around zero or negative. These phases do not adsorb superplasticizers. Consquently, a hydrating cement grain is best represented by a mosaic structure, with superplasticizer molecules mainly adsorbed on ettringite spots.
出处
《建筑材料学报》
EI
CAS
CSCD
2007年第1期7-13,共7页
Journal of Building Materials
