Influence of carbon nanotubes and polycarboxylate superplasticiser on the Portland cement hydration process

Research on the performances of VPEG macromonomer grafted different functional groups to prepare polycarboxylate superplasticizers

“…Figure 8b shows the change of heat released during the hydration process of cement, and it can be found that the amount of heat released cement by mixed with different PCEs and the blank group were different, but the consistency was that the exothermic change of hydration of cement paste was rapid before 32 h, and it tended to be stabilized after 32 h. When the hydration of cement paste reached 72 h, the hydration exotherm of cement paste mixed with V‐SMAS was the largest, followed by V‐N‐MAM, V‐AM, V‐AA, and V‐AMPS. This is due to the introduction of different functional groups that make the molecular structure form of the synthesized PCE different, its adsorption on the surface of the cement particles lead to changes in the morphology of the water compounds, thereby affecting the heat release of cement hydration 43 …”

“…This is due to the introduction of different functional groups that make the molecular structure form of the synthesized PCE different, its adsorption on the surface of the cement particles lead to changes in the morphology of the water compounds, thereby affecting the heat release of cement hydration. 43 Figure 8c shows the change of cement hydration rate, and it can be seen that compared with the blank group, the induction period of cement mixed with PCEs were prolonged, in which the induction period of the blank group was about 4h15min, while the induction period of the samples mixed with PCEs were extended by 1 h 55 min $ 3 h 45 min than the blank group. This is due to the PCE molecular structure contains hydroxyl ( OH À ), carboxyl ( COO À ), sulfonic acid group ( SO 3 À ) and other functional groups, which will be complexed with the Ca 2+ in the cement, thereby inhibiting the hydration of the hydration mineral hydration and growth, and it takes more time to overcome the hydration energy barriers, so the induction period of the cement blended into the different PCEs were prolonged.…”

Cement Composites with Carbon‐Based Nanomaterials for 3D Concrete Printing Applications – A Review

“…Li et al [87] demonstrated an improvement in the dispersion of GO in a cement pore solution with the use of silica fume, without which the GO agglomerated in the presence of divalent calcium ions in the pore water and cement paste. Wang and Li [88] dispersed MWCNTs in an aribic gum surfactant at a 1 : 6 (MWCNTs: dispersant) ratio followed by ultrasonication for 30 min., while carboxymethyl cellulose (CMC) dispersant was utilized by Karpova et al [89] to disperse MWCNTs into distilled water through ultrasonication for about 6 min. to prepare MWCNTs/CMC suspensions.…”

“…The incorporation of SWCNTs with AEA and DOC agents increased the yield stress and decreased the plastic viscosity of the composite compared to that of the plain cement mixtures. Karpova et al [89] reported that a complex admixture containing carboxymethyl cellulose/MWCNTs suspensions and polycarboxylate ether plasticizer reduced the heat of hydration of the cement by 72 % and 26 % after 24 h and 48 h, respectively. Similarly, the cement composites workability reduced with the incorporation of rGO because of formation of flocculated structures of rGO with the cement owing to its increased surface area and functional groups.…”

“…The incorporation of SWCNTs with AEA and DOC agents increased the yield stress and decreased the plastic viscosity of the composite compared to that of the plain cement mixtures. Karpova et al [89] . reported that a complex admixture containing carboxymethyl cellulose/MWCNTs suspensions and polycarboxylate ether plasticizer reduced the heat of hydration of the cement by 72 % and 26 % after 24 h and 48 h, respectively.…”