Fuerzas de repulsión de aditivos superplastificantes en sistemas de escoria granulada de horno alto en medios alcalinos, desde medidas AFM a propiedades reológicas

摘要

[EN]The electrostatic and steric repulsion induced by different\udsuperplasticizers on ground granulated blast furnace slag\udin alkaline media have been studied. The superplasticizers\udwere sulfonated naphthalene, sulfonated melamine, vinyl\udcopolymer, and polycarboxylate- based admixtures. With\udthese superplasticizers the slag suspensions had negative\udzeta potentials, ranging from -3 to -10 mV. For the first\udtime the adsorbed layer thicknesses for superplasticizers\udon slag using colloidal probe atomic force microscopy\udhas been measured. To model the interparticle force\udinteractions an effective Hamaker constant was computed\udfrom dielectric properties measured on a dense slag\udsample produced by spark plasma sintering. The obtained\udresults conclude that the dispersion mechanism for all the\udsuperplasticizers studied in the present work is mainly\uddominated by the steric repulsion. Results were then used\udin a yield stress model, YODEL, to predict the yield stress\udwith and without the superplasticizers. Predictions of the\udyield stress agreed well with experimental results.