Synthesis and optimization of a montmorillonite-tolerant zwitterionic polycarboxylate superplasticizer via Box-Behnken design

Abstract

This is a 'preproof' accepted article for Clay Minerals. This version may be subject to change during the production process.

Synergistic Effect of Polycarboxylate Superplasticiser and Protein Retarders in Cementitious Materials Containing Na- Montmorillonite: Effect of Addition Methods

“…As shown in the figure, regardless of the addition method, the higher substitution ratio led to the thinner thickness of adsorption of the PCE. This result was similar to Li’s results—that the thickness of adsorption layer increased with increasing Mmt content [ 67 ], which could be due to trapping the side chain of the PCEs within the interlayer of Mmt, leading to the suppressed steric repulsion of PCE [ 52 ]. However, it is not surprising that when the separate addition method is applied, the thickness of the adsorption layer is further increased, with thickest layer being observed by DA.…”

“…The intercalation between the PCE and the Na-Mmt was calculated from the d-spacing of the silicate layers (d 001 ) and of the Mmt, and the XRD patterns of Na-Mmt under different addition method are plotted in Figure 7 . As shown in the figure, under the SA, the d-spacing of the Na-Mmt was 1.82 nm, which was similar to the other reports of Mmt with the trapped side chain of PCEs [ 52 ]. However, when the separate addition was applied, the d-spacing was decreased to 1.69 nm by PA and 1.46 nm by DA, respectively.…”

“…The adsorption amount of PCE with Na-Mmt was determined by Total Organic Carbon (TOC) Equipment (Multi N/C 2100 Jena, Germany) followed by the previous study [ 52 ]. For testing, a mixture of 0.50 g Na-Mmt, 24.50 g of synthetic cement pore solution (prepared by dissolving 1.72 g CaSO 4 ·2H 2 O, 4.76 g K 2 SO 4 , 6.96 g Na 2 SO 4 , and 7.12 g KOH in 1 L of deionized water [ 53 ]) and the according amount of PCE were added into a 50 mL container and stirred for 9 min.…”

“…The interlayer spacing (d-spacing) of multiple layers of Na-Mmt with PCE were determined by XRD with CuKα radiation (D8 type XRD machine by Bruker, Germany) [ 52 ]. The characterisation was conducted with the diffraction angle (2θ) between 2° to 40° under a scanning speed of 2°/min.…”

Effect of Salinity and Polycarboxylate Superplasticizer on Fresh Property of Seawater-Blended Cement

“…As further illustrated in Figure 15 b, increased SW salinity further decreased the thickness of the adsorbed PCE layer, and the reduction was more pronounced when high salinity was applied (HSW). The reasons for this could be that (1) the higher ion strengths in SW shrunk the conformation of the PCEs, which reduced the steric repulsions of the PCEs as demonstrated by Figure 5 ; (2) the accelerated hydration in SW-blended cement paste generated more hydration products, consuming the PCEs by intercalation actions [ 62 ].…”