Experimental determination of the effective anionic charge density of polycarboxylate superplasticizers in cement pore solution

Calcium complexation and cluster formation as principal modes of action of polymers used as superplasticizer in cement systems

“…Results are given in Table 3. As expected and in accordance to others [19], the number of anionic charges of PNFS exceeds that of the PCEs. SP1 exhibits an increased number of anionic charges with respect to SP12 at equal dosage.…”

“…As documented in literature, anionic charges of polymers are able to complex cations [18,19,36]. This complexation was quantified in the present work by measuring Ca ion activity by a Ca selective electrode.…”

“…Charge titration experiments were performed in an automatic titrator (Mütek PCD 03, Germany) according to the protocol given by Plank and Sachsenhauser [19]. Electrical current caused by counter-ions, which are removed by vertical oscillation of a plunger from the superplasticizer sample, was measured.…”

“…Due to their anionic charge [18] and the aqueous (pH) environment in cement pastes, functional groups of the polymers of superplasticizers are able to complex ions [19]. In cementitious systems, mainly calcium is bound by SPs.…”

Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives

“…SPs present different chemical compositions, such as lignosulfonates, sulfonated melamine-based polymers or polycarboxylate-based compounds (PCE) [4]. The latter are belonging to the last generation of SPs and consist of a main linear backbone (polymethacrylic acid) with carboxylate groups, some of them grafted with side chains with ether functionalities (polyethylene oxide units) [5]. The length of both backbone and side chains can be variable, thus giving rise to a different effectiveness.…”