PCE结构对硅酸三钙结构和形貌的影响

Effect of PCE Structure on the Structure and Morphology of Tricalcium Silicate

为了进一步了解减水剂与水泥矿物相的相互作用,分别采用X射线光电子能谱（XPS）和扫描电子显微镜（SEM）研究了聚醚型聚羧酸减水剂（PCE）结构对硅酸三钙（C3S）水化产物表面电子状态和形貌的影响.结果表明：在吸附了PCE的样品中,C—H的C1s谱峰明显增强,并出现C—O的C1s谱峰,而Si2p谱峰明显减弱,PCE在C3S表面的吸附膜厚度为0.94-1.40nm;由于Ca元素填充于PCE吸附膜中,导致C3S表面的Ca2p谱峰强度变化较小;PCE结构对Si2p,Ca2p谱峰的化学位移影响显著,即PCE的羧酸根密度越大,样品的化学位移越明显;PCE结构不同,抑制C3S水化的程度也不同,并且PCE还可阻止C3S的水化产物相互黏结.

To further understand the interaction between polycarboxylate superplasticizers（PCE） and the mineral phases of cement, the effect of PCE with different structure on the electronic state and the morphology of the hydration products of tricalcium silicate（C3S） were investigated by XPS and SEM. The resuits show that, the intensity of Cls photoelectron of C--H in the sample with adsorbed PCE enhanced obviously, and the Cls spectrum of C--O appeared. However, the intensity of Si2p photoelectron of the samples with adsorbed PCE reduces greatly and the adsorption thickness was in the range of 0.94 nm to 1.40 nm. The attenuation degree of Ca2p XPS scanning spectrum was small because the adsorption layer was filled with calcium. In addition, all the samples with adsorbed PCE have chemical shift in different extent and the chemical shift increases with the decrease of the side chain density. According to the SEM resuits, the PCE could hinder the adhesion of the hydration products of C3 S. Besides, the hydration degree of C3 S will decrease with the decrease of the side chain density.