Influence of Titanium Dioxide Nanoparticles on the Sulfate Attack upon Ordinary Portland Cement and Slag-Blended Mortars

Abstract

In this study, the effects of titanium dioxide (TiO2) nanoparticles on the sulfate attack resistance of ordinary Portland cement (OPC) and slag-blended mortars were investigated. OPC and slag-blended mortars (OPC:Slag = 50:50) were made with water to binder ratio of 0.4 and a binder to sand ratio of 1:3. TiO2 was added as an admixture as 0%, 3%, 6%, 9% and 12% of the binder weight. Mortar specimens were exposed to an accelerated sulfate attack environment. Expansion, changes in mass and surface microhardness were measured. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Thermogravimetry Analysis (TGA) and Differential Scanning Calorimetry (DSC) tests were conducted. The formation of ettringite and gypsum crystals after the sulfate attack were detected. Both these products had caused crystallization pressure in the microstructure of mortars and deteriorated the mortars. Our results show that the addition of nano-TiO2 accelerated expansion, variation in mass, loss of surface microhardness and widened cracks in OPC and slag-blended mortars. Nano-TiO2 containing slag-blended mortars were more resistant to sulfate attack than nano-TiO2 containing OPC mortars. Because nano-TiO2 reduced the size of coarse pores, so it increased crystallization pressure due to the formation of ettringite and gypsum thus led to more damage under sulfate attack.

Experimental study on sulfate erosion resistance of nano-CaCO3 modified concrete

“…In the experimental study, Atta-ur-Rehman et al studied the effects of titanium dioxide (TiO 2 ) Nanoparticles on the sulfate attack resistance of ordinary Portland cement (OPC) and slag-blended concrete, the results show that nano-TiO 2 containing slag-blended concrete were more resistant to sulfate attack than nano-TiO 2 containing OPC concrete (Atta-ur-Rehman et al 2018).…”

Short-Term Performance of Sustainable Silica Fume Mortars Exposed to Sulfate Attack

“…On the other hand, sulfate attack is another pathology which could produce a deleterious effect in cement-based materials and structures [20,21], such those in contact with aggressive soils and waters. The classic harmful effects of this attack (ettringite and gypsum formation) are associated with the sulfate anion.…”

Photocatalytic and Pozzolanic Properties of Nano-SiO2/Al2O3-TiO2 Powder for Functional Mortar

“…Therefore, the CH crystals in the mortar can be refined to reduce the negative impact on the matrix strength by CH. In addition, the strength of mortar is considered to be improved because the matrix is smaller which increases the density to reduce the filling effect and the number of harmful holes [38].…”