Competitive adsorption and interaction between sodium alginate and polycarboxylate superplasticizer in fresh cement paste

In this study, sodium alginate (SA) was investigated for the first time as an auxiliary material in a polycarboxylate superplasticizer (PCE) system, and its interaction mechanism in a PCE-cement system was investigated, which is desirable to enhance the dispersion retention and solve the bleeding and segregation of fresh cement paste. Through the investigate of the adsorption and interaction of SA in cement or cement PCE system, the mechanism of SA improving the dispersion and other properties of cement paste was obtained. Results detailed from rheological measurements revealed that SA exhibits water retention and dispersion properties in a PCE-cement system: before the content of SA is lower than 0.01g, SA has a positive effect on the viscosity of PCE-cement paste, and the dispersion of cement paste will have a synergistic effect with PCE. When the amount of SA reaches 0.2g, all the results are opposite. In the meantime, the competitive adsorption effect of between SA with PCE becomes larger and the dispersion performance will get worse from the research results of rheological analysis. Similar phenomena have been proved from the total organic carbon analysis and thermogravimetric analysis revealed that SA is easily adsorbed on cement via complexation with calcium ions than PCE, the interaction between SA and calcium ions was explained by conductivity and dynamic light scattering measurements. FT-IR and TEM showed that PCE and SA could be adsorbed on the cement particles, an...
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Category: Chemistry Source Type: research