Adsorption interaction between cement hydrates minerals with fluid loss additive investigated by fluorescence technique

The mechanism of synthetic polymer fluid loss additive (FLA) was based on adsorption of FLA on the surface of hydrating cement particles and the formation of a complex network structure, resulting in decline of cement slurry filtrate. However, due to the complexity of early hydration environment of cement slurry, there was lack of effective and intuitive way to characterize the adsorption interaction between FLA and cement particles. In this study we described our quest in furthering understanding of the adsorption action of fluid loss additive on the cement minerals. By fluorescence staining technique (combined polymer additives with organic fluorescent dyes), we observed that the skin of the hydrated particles was coated with dyed polymer, which led to a successful fluid loss additive. More importantly, the analysis of the fluorescence intensity of luminous polymer in cement pore solution distinguished the respective adsorption capacity of various admixtures (dyed and undyed) on the surface of the cement particles, so as to solve the problem of the traditional method in characterizing the competitive adsorption between polymers, thus gave a convenient way to analyze the interaction mechanism between polymer admixture and cement particles from the theory and technology.