Potential Effect of Surface Modified Nano‐SiO₂ with PDDA on the Cement Paste Early Hydration

Abstract

The potential application of surface modified nano‐SiO2 (NS) particles with poly (dimethyl diallyl ammonium chloride) (PDDA) has been reported in other fields, but not in civil construction. This paper aims to assess the influence of surface modified NS with PDDA on the early‐age hydration of cement paste, where cement is replaced by 0.3%, 1% and 3% of NS particle. PDDA can be introduced onto the surface of NS via long‐distance charge pairs. Calorimetric measurements of cement pastes with 0.35 w/b (water/binder) ratio show that NS particles accelerate the cement hydration, while PDDA retards it. Moreover, the cement hydration is controlled by PDDA at lower dosage of NS/PDDA particle, which delays the exothermic peaks of cement hydration, while the cement hydration is controlled by NS particle aggregates at higher dosage of NS/PDDA particle. Based on the results above, the mechanism of the adsorption of NS/PDDA particle on cement particle surfaces is proposed.

Non-iridescent and Wide-Color-Range Structural Coloration Enabled by Cellulose Nanocrystals with a Controlled Long-Range Photonic Structure and Helical Pitch

“…CNC/Gly suspension shows negative ζ potential due to the sulfate ester groups (−O−SO 3 −), while PDDA is a strong cationic polyelectrolyte. 35,36 During the solvent evaporation process, the self-assembly of CNCs into a periodic helical ordered structure is influenced as a result of electrostatic attraction between CNCs and PDDA (ζ potential of the composite suspensions is shown in Figure S6). Similar to a previous work on the crosslinking of the hydroxypropyl cellulose mesophase with glutaraldehyde, 25 local disordered structures appear in the periodic layered arrays of CNCs after the introduction of PDDA; the cholesteric liquid crystal domains are tilted and deformed, presenting order/disorder multidomain structures.…”

Influence of functionalized nanosilica with different functional groups in the properties of cementitious composites: A review

“…The only difference observed was that the peak of sulfate depletion was greater than the peak of hydration of silicates for samples with NS@PCE. (Huang et al, 2020) In the cement paste with 0.3% NS@DADMAC, a delay in the peak of hydration from 9.4 to 9.8 hours was observed. When the NS@DADMAC dosage increased from 0.3% to 1%, NS @ DADMAC accelerated the hydration of the cement instead of slowing it down.…”

Nano-SiO2 used with cationic polymer to improve the strength of sack paper

“…The new peak at 1673 cm -1 was attributed to the -OH bending vibration of the SiO2 nanoparticles (Kong et al 2020). The peaks of 1521, 1462, and 1038 cm -1 in the handsheet samples with the SiO2 nanoparticles and PDADMAC were the characteristic bonds of the C-C of the PDADMAC, the Si-O of the SiO2 nanoparticles, and the C-N of the PDADMAC stretching vibrations, respectively (Huang et al 2020). The ATR-FTIR results confirmed that the SiO2 nanoparticles were effectively retained in the handsheets.…”