Effects of Modified Nano-SiO2 Particles on Properties of High-Performance Cement-Based Composites

Abstract

In this research, silane coupling agent was used to modify the surface of nano-SiO2, particles and the effects of modified nano-SiO2 particles on the mechanical properties of high-performance cement-based composites and its mechanism were systematically studied. The results indicated that the optimum modification parameters were a coupling agent content of 10%, reaction temperature of 65 °C, and reaction time of 8 h. Compared with the unmodified nano-SiO2, the modified nano-SiO2 promoted and accelerated the hydration process of cement. The pozzolanic effect, filling effect, and nucleation effect of modified nano-SiO2 made the microstructure of the composite more compact, and thus improved static mechanical properties of cement-based composites.

Physical Properties and Durability of Lime-Cement Mortars Prepared with Water Containing Micro-Nano Bubbles of Various Gases

“…The compressive strength clearly increases along with the quantity of MNB. Nanomaterials, due to their large specific surface, are characterized by increased chemical reactivity, which is suggested by the afore-mentioned literature sources [ 10 , 11 , 12 , 13 , 14 , 15 ]. The application of micro-nano gas bubble water could accelerate the chemical reaction in the course of curing.…”

“…The nanosilver addition confers the bactericidal and fungicidal properties to concretes [ 5 , 9 ]. In turn, nano SiO 2 increases the pozzolanic reactivity of a concrete mixture, improves the compressive strength, as well as decreases porosity and water absorptivity [ 10 , 11 ]. The C-S-H nanoparticles accelerate the increase of concrete early strength [ 12 ].…”

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

“…The authors attributed this behavior to the effects of nucleation and refinement of the microstructure. The compressive strength of cement pastes containing NS@GO was 28.2% greater than that of the reference sample (paste without the addition of NS) (Rong et al, 2020). 3, 7 and 28 daysThe FNS with better dispersibility can accelerate the hydration of the cement and fill the internal voids in the paste.…”

“…However, the effect of NS@DADMAC on accelerating cement hydration did not increase significantly when the content was increased to 3%. (Rong et al, 2020) The authors investigated 5 specimens and obtained relatively close hydration heat curves. The period of acceleration of the hydration of the samples without NS was about 15 to 20 hours.…”

“…The mechanical performance was evaluated between 12 hours and 28 days of hydration. For all investigated NS functionalizing agents (polycarboxylate-based superplasticizer additive -PCE Sun et al, 2017), shrinkage-reducing additive -SRA (Gu, Wei, et al, 2017), graphene oxide -GO (Gu et al, 2020), amine groups (Rong et al, 2020;Vasconcellos et al, 2020)), an increase in the mechanical performance of pastes was observed after 7 days of hydration.…”