Title: Nucleation and Growth of C-S-H – PCE Used as Strength Enhancer in Cement
Author(s): Vipasri Kanchanason and Johann Plank
Publication: Symposium Paper
Appears on pages(s): 67-76
Keywords: calcium silicate hydrate; polycarboxylate; non-classical nucleation; globules; nanofoils; early strength
The influence of an isoprenyl oxy poly(ethylene glycol) (IPEG) based PCE on the nucleation and crystallization of C-S-H precipitated from aqueous solutions of Ca(NO3)2 and Na2SiO3 was investigated. It was found that in the absence of IPEG-PCE, globular nanoparticles of C-S-H with a diameter of ~50 nm [1.97 x 10-6 in.] are formed. Subsequently, within an hour the globules convert to C-S-H nanofoils with ~150 nm [5.91 x 10-6 in.] length following a non-classical nucleation mechanism. In the presence of the PCE, the initial globules show a core-shell structure whereby a layer; presumably PCE polymer, coats the C-S-H core. The shell around the C-S-H globules delays the conversion to the nanofoils for several hours and leads to significantly smaller foils and a superior seeding material in cement.