Effects of AMPS-NNDMA and polycarboxylate superplasticizer on the adsorption and hydration properties of tricalcium silicate

The adsorption of AMPS-NNDMA and PCE when used as a single additive and in combinations of both admixtures on C3S was measured. An SEM test and XRD test were used to measure the hydration products of C3S in presence of PCEs and/or AMPS-NNDMA. It was found that the addition of AMPS-NNDMA was favorable for the adsorption of PCE and the addition of PCE has negative effect for the adsorption of AMPS-NNDMA. The adsorption of PCE hindered adhesion of the hydration products of the C3S. A honeycomb structure formed on the surface of the hydration products of the C3S under AMPS-NNDMA without PCE, and this phenomenon did not take place in the samples with the further addition of PCE. The morphologies of the hydration products of C3S with different kinds of AMPS-NNDMA had little distinction. The adsorbed AMPS-NNDMA influenced the formation and dissolution of CH. The amount of CH that the hydration products of C3S formed under 0.5 g/L of AMPS-NNDMA without PCE decreased after 15 min, while it increased under 0.5 g/L of AMPS-NNDMA with 0.5 g/L of PCE.