Effect of Carbon‐Based Materials on the Early Hydration of Tricalcium Silicate

Abstract

Two types of carbon-based materials, i.e., mesoporous carbon and HNO 3 -oxidized carbon nanotubes, with nearly the same specific surface area and abundant in surface oxygen-containing functional groups were selected in order to examine their effect on the hydration of tricalcium silicate (C 3 S), the main portland cement component, in early stages. Different methods, including XPS and TG-MS analyses, electrokinetic potential measurements, as well as determination of adsorption capacity for calcium ions from aqueous solutions, were used to investigate the physicochemical surface properties of the selected carbon-based materials. It was found that the carbon-based materials with high specific surface area and rich in oxygencontaining functional groups on their surfaces have a catalytic effect on early C 3 S hydration. It was observed that the modification of C 3 S paste with the selected materials added in high concentrations (1 wt% and higher) led to an increase in the rate and degree of C 3 S hydration in the early stages. The mechanism of early C 3 S hydration accelerated by carbon-based materials rich in surface functional groups was clarified by the example of the mesoporous carbon. It was found that the oxygen-containing functional groups present on the carbon surface have both an influence on the content of calcium ions in the aqueous phase of the C 3 S paste and an indirect positive effect in relation to the specific surface of C 3 S.

Self-sensing Piezoresistive Composites Based on Cement Incorporating Low Dosage of Carbon Black Used as Multifunctional Construction Materials

“…Also a densification of cement stone and increase of hydrates sizes for longer curing times (90 and 180 days) can be noticed. The presence of CB nanoparticles determine an increase of sizes of hydrates, suggesting a positive effect exerted by CB powder on the cement hardening; one can conclude that CB nanoparticles act as nucleation sites for the hydrates resulted in cement hydration process, in good correlation with the results reported by other researchers [46][47][48][49][50]. This type of impedance plots fits to the conventional equivalent circuit (Figure 7), formed by a series of two sub-circuits of parallel resistors (R) and constant phase elements (CPE).…”

Effect of Ultrafine Additives on the Morphology of Cement Hydration Products

“…This aspect can indicate the lack of chemical interactions between nanotubes and cement hydration products. The inert character of carbon-based materials without additional functionalization was also highlighted in previous research [12,42]. MWCNTs in the bottom-left corner of the SEM image have a curved shape, which can be caused by the high differences between the diameter of the nanotubes and their length.…”

Dispersion and effects of metal impregnated granular activated carbon particles on the hydration of antimicrobial mortars

“…The Ca 2+ ion affinity of the GACs used in this study was assessed for their adsorptive capacity of Ca 2+ ions under water quality conditions that mimic those typically found in the pore solution of cement paste. Following the methodology used by Sobolkina et al [38], a series of batch sorption experiments were executed. A total amount of 2 g of GAC (GAC-U and GAC-A) were dispersed in 40 mL of a 0.10M NaOH solution (pH 12.8) at different initial Ca 2+ concentrations (400 and 1320 mg/L), using Ca(NO3)2 as the Ca 2+ source.…”

“…Metals that are released into the pore solution of cementitious materials can react with, or otherwise sorb to, colloidal gellike particles (i.e., C-S-H) and/or form new compounds, including stable metal hydroxides [36,37]. The early-age effects of different types of carbon-based materials (with no metals) on the kinetics of tricalcium silicate (C3S) hydration have been reported by Sobolkina et al (2016) [38]. In this work, mesoporous carbon (mean size of 13.9 μm) and HNO3-treated carbon nanotubes (CNT) were found to have a catalytic effect on early C3S hydration.…”