Photocatalytic Activity and Mechanical Properties of Cement Slurries Containing Titanium Dioxide

Abstract

The effect of titanium dioxide (TiO2) on the mechanical properties of cement slurries including their benefits on air purification and abatement of pollutants is not well documented. Cementitious-based slurries are typically applied in thin layers as decorative coatings for existing facades, protection against an ingress of aggressive ions, or rainproof covers to minimize water penetration. Different parameters including the TiO2 concentration, dispersion time during batching, and applied thickness on top of existing mortar blocks are investigated in this paper. Tested properties included the flow, colorimetry, compressive/flexural strengths, bond to existing substrates, water absorption, and photocatalytic activity evaluated using an ISO 22197-1:2007 reactor. The results showed that the mechanical properties remarkably improved with TiO2 additions, up to 8% of the cement mass. This was attributed to two concomitant phenomena including a micro-filler effect that enhances the packing density and nucleation sites to promote strength development. The removal of nitrogen oxides from the atmosphere reached 92% when the TiO2 was added at a rate of 5% of the cement mass. Such data can be of particular interest to consultants and environmental activists searching for innovative materials capable of maintaining better ambient air quality in urban and modern cities.

Assessment of Photocatalytic Nano-TiO2 Mortars’ Behavior When Exposed to Simulated Indoor Conditions of Glazed Buildings

“…Based on Figure 10a, the compositions with TiO2 exposed to the external conditions representing outdoor environments (receiving direct sunlight radiation) had higher final lightness values when compared to the control groups, as expected and similarly to other studies [4,6,15,68], except for photocatalytic mortars produced with a 1:4 cement:sand ratio. Thus, although RhB may experience a dye-sensitized photoreaction [69], the increased results when in the presence of the photocatalyst probably demonstrate the occurrence of the catalytic process.…”

“…Overall, in the three types of compositions with TiO 2 addition, the fresh state density was higher than the control samples without the photocatalyst. This behavior was also observed in another study by Jabali et al [4]: when TiO 2 content increased, the fresh density values of mortars were also higher. This assertion finds support in the research of Naganna et al [48], who concluded that TiO 2 nanoparticles serve as effective nanofillers, enhancing the concrete's resistance to water permeability.…”

“…The results for the mortars' characterization in the fresh state are shown in Table 2, and for the 28 day set of experiments in Tables 3 and 4. Regarding the flow-table test, the range of consistency index (Table 2) was intentionally set as 240 mm ± 20 mm, a usual workability found for rendering mortars [4,31], and for which water quantities were adjusted.…”

“…The primary sources of pollutant particles that might adhere to building envelopes include motor vehicles, industries, and power plants-which are also the main contributors to air pollution [4]. Among the common air pollutants that affect building materials are nitrogen dioxide, ozone, carbon dioxide, chlorides, sulfur dioxide, nitrates, and volatile organic compounds (VOCs) [5].…”

Evaluating Sustainable Colored Mortars Reinforced with Fly Ash: A Comprehensive Study on Physical and Mechanical Properties under High-Temperature Exposure

“…In examining Table 9 and Figure 11b, the 90-day RFS values post-exposure to 800 In examining Table 9 and Figure 11b, the 90-day RFS values post-exposure to 800 exhibited a decrease of 72.04% in the R0 control example, 61.46% in the R1 sample, b tween 60.25% and 61.84% in the YP-doped R2-R4 examples, and between 61.20% a 63.75% in the RP-doped R5-R7 examples. Comparing the YP and RP-added mortar exa ples, YP demonstrated a superior filler effect due to its finer grain size, marginally enhan ing RFS capacities compared to RP [61][62][63]. Furthermore, akin to the RCS results, utilizi YP and RP at 1% and 3% levels enhanced the RFS capacity of the samples by over 5%.…”