Effects of nano-TiO₂ on properties of cement-based materials

Abstract

The effect of titanium dioxide (TiO 2 ) nanoparticles on early age and long-term properties of cement-based materials is examined experimentally through isothermal calorimetry, chemical shrinkage, setting time, compressive strength and surface microhardness, where part of the cement is replaced with TiO 2 : Early age hydration is accelerated by TiO 2 nanoparticles which also increase degrees of hydration of Portland cement, as evidenced by isothermal calorimetry and chemical shrinkage results. With increasing amounts of TiO 2 , setting time is reduced, despite decreasing cement content, due to TiO 2 replacement, again showing accelerated hydration. Comparing TiO 2 -cement composites from two different TiO 2 manufacturers, results suggest that size of nanoparticles and dispersability are critical in the rate of hydration, with smaller size agglomerates, but not necessarily smaller size particles, producing a greater effect. Compressive strength increases with higher TiO 2 nanoparticle replacement at lower water-to-solids ratio (w/s 0 . 40) and strength is not compromised by up to 10% TiO 2 replacement at higher w/s 0 . 60. However, microhardness of the composite decreases with higher TiO 2 amount. Broadly, these results indicate that mineral addition as cement replacement can be optimised in terms of dosage and dispersability to achieve lower cement fractions without compromising strength, but that the potential for reductions in hardness should be considered.

Thermal and Mechanical Properties of Cement Mortar Composite Containing Recycled Expanded Glass Aggregate and Nano Titanium Dioxide

“…This behavior was attributed to the addition of nTiO2 into the cementitious materials, which resulted in an accelerated rate of hydration process. A similar attribute has been reported in previous studies that when nTiO2 is uniformly distributed throughout the matrix, the hydration process and formation of C-S-H gel is accelerated, which results in early strength [32,[47][48]. In the other set of mixes, the effect of nTiO2 inclusion on the compressive strength of mixes was investigated after a different curing time.…”

Effect of TiO2 Nanoparticles on Physical and Mechanical Properties of Cement at Low Temperatures

“…erefore, nanoparticles could be considered as an alternative choice to serve as accelerators for cementitious materials under low temperatures. Numerous studies have been conducted on the utilization of nanoparticles, including nano-SiO 2 [12][13][14][15][16][17][18][19][20][21][22], nano-CaCO 3 [17,23,24], nano-Al 2 O 3 [16,20,25], nano-TiO 2 [14,16,[26][27][28][29][30][31][32][33][34][35][36][37][38], nano-Fe 2 O 3 [10,13], and nano-CuO [13,39], in cementitious materials to improve their durability and mechanical properties. Nano-SiO 2 is the most commonly used nanoparticle, while nano-TiO 2 is comparatively favorable for pavement structures in terms of aircleaning property.…”

“…With respect to TiO 2 nanoparticles, the study by Nazari et al showed that partial replacement of cement with TiO 2 nanoparticles reduced the setting time, enhanced the hydration process, and increased the flexural strength of concrete at the temperature of 20°C, while the flexural strength reduced when the content of TiO 2 nanoparticles was more than 4% [26][27][28][29]. Lee et al reported that, through the addition of TiO 2 nanoparticles, the early-age hydration of cement was accelerated, the setting time was reduced, and the compressive strength was increased at 23 ± 2°C [31,32]. Pimenta Teixeira et al indicated that high temperature (40°C and 60°C) facilitated the hydration of cement paste containing TiO 2 nanoparticles and improved the early-age compressive strength [34].…”

The Effect of Curing Temperature on the Properties of Cement Pastes Modified with TiO2 Nanoparticles

“…The influence of TiO 2 nanoparticles on the hydration of cementitious materials was examined by researchers [15,16,17] and shown to enhance hydration due to the high surface area of these nanoparticles, increasing the nucleation sites for the hydration reaction. Lee et al [18] reported that compressive strength increased by up to 10% TiO 2 nanoparticle replacement at a low water-to-cement ratio (0.4) and did not show degradation at high water-to-cement ratios (0.6). Zhang et al [19] demonstrated that TiO 2 nanoparticles improved the compressive strength and mitigated the drying shrinkage of cementitious materials.…”