Mechanical, electrical and microstructural studies on nano-TiO₂ admixtured cement mortar cured with industrial wastewater

Abstract

Nanotechnology has attracted the attention of building materials over the last decade. Nano-size particles-cement mortar-can positively alter their early and hardened properties. The objective of this study is the inclusion of TiO 2 nanoparticles (NT) as an admixture (2 to 10% by weight of the cement) on the mechanical, electrical, and microstructure properties of cement mortar composites and cured with industrial wastewater. Nowadays, the analysis of TiO 2 nanoparticles in concrete has been recognized increasingly. Nevertheless, there has been no report of the durability problems on nano-TiO 2 admixtured cement mortar cured with industrial wastewater. To achieve this purpose, compressive strength, porosity, electrical resistance, rapid chloride penetration test, and scanning electron micrograph (SEM) were performed to find out the relationship between the mechanical, microstructure, and electrical properties of NT mortar composites. The test results showed that TiO 2 nanoparticles treated with industrial wastewater improve early-age hydration. For increasing replacement percentages of TiO 2 , the setting time is reduced due to the substitution of TiO 2 , despite declining cement content, which again indicates accelerated hydration. However, when NT and wastewater were mixed, porositytest results indicated significant improvements in microstructure, resulting in the development of a more compact and durable hardened structure. Consequently, the combination of NT and wastewater cure has resulted in the development of mortar strength and durability. Eventually, 10% NT seems to be a decent substitute for economic efficiency and hardened properties.

A review of the effect and optimization of use of nano-TiO2 in cementitious composites

“…This was attributed to the high specific surface area of nanoparticles that adsorbs part of the water and superplasticizer. Gopalakrishnan et al [52] reported a reverse relationship between the content of NT and flow of mortars. Joshaghani et al [35] tested the effect of 3.0 and 5.0 wt% (by weight of the binder) nano-TiO2 on the fresh properties of self-compacting concrete using slump flow, L-box, V-funnel and column segregation tests.…”

“…Titania nanoparticles has been also found to behave as an activator to accelerate pozzolanic reaction, to increase the rate of cement hydration, to increase the intensity of the heat peak, and to reduce the initial and final setting time [14,24,28,37,44,45,52,58,60,61]. The reduction in the setting time was found to be proportional to the content of the added nano-TiO2 [20,40,52,58]. Reduction in setting time could lead to reduction in total time of construction which is economically beneficial [45].…”

“…Such functionalities have the potential to improve the sustainability of construction materials [45]. Furthermore, despite being chemically inert in terms of its potential to directly react during cement hydration [19,24,40,44,45], nano-titanium dioxide can generally improve the mechanical performance and durability, as well as decrease the rigidity of cementitious materials [20,28,31,35,37,44,[51][52][53][54][55][56]. Moreover, the flexural fatigue performance and abrasion resistance of concretes was reported to be remarkably improved with the use of TiO2 nanoparticles [31].…”

“…Addition of TiO2 nanoparticles leads to greater homogeneity, better compaction, reduction in the pore volume and the pore size of cementitious materials, which results in remarkable reduction in permeability [20,31,35,44,[56][57][58][59]. Titania nanoparticles has been also found to behave as an activator to accelerate pozzolanic reaction, to increase the rate of cement hydration, to increase the intensity of the heat peak, and to reduce the initial and final setting time [14,24,28,37,44,45,52,58,60,61]. The reduction in the setting time was found to be proportional to the content of the added nano-TiO2 [20,40,52,58].…”

Comparative Overview of the Performance of Cementitious and Non-Cementitious Nanomaterials in Mortar at Normal and Elevated Temperatures

“…However, the addition of nanomaterials accelerates the hydration process and enhances the formation of C–S–H gel (as marked by yellow hexagons), which makes the microstructure denser, thereby increasing the strength and durability of the treated sample. However, non-uniform dispersion or excessive addition of nanomaterials (beyond an optimum dosage) leads to agglomeration and formation of weak bonds in the mortar sample [ 77 , 148 , 149 , 150 ]. Ling et al [ 13 ] observed that the inclusion of nano-silica in the mortar reduces the pores, concentrates the matrix, and enhances the strength of cementitious composites by improving the adhesion of the hydration products with the PVA fibers.…”