No abstract

This paper investigates the effect of curing temperature on the hydration, microstructure, compressive strength, and transport of cement pastes modified with TiO2 nanoparticles. These characteristics of cement pastes were studied using non-evaporable water content measurement, X-ray diffraction (XRD), compressive strength test, electrical resistivity and porosity measurements, and scanning electron microscopy (SEM). It was shown that temperature enhanced the early hydration. The cement pastes cured at elevated temperatures generally showed an increase in compressive strength at an early age compared to the cement paste cured at room temperature, but the strength gain decreased at later ages. The electrical resistivity of the cement pastes cured at elevated temperatures was found to decrease more noticeably at late ages compared to that of the room temperature cured cement paste. SEM examination indicated that hydration product was more uniformly distributed in the microstructure of the cement paste cured at room temperature compared to the cement pastes cured at elevated temperatures. It was observed that high temperature curing decreased the compressive strength and electrical resistivity of the cement pastes at late ages in a more pronounced manner when higher levels of TiO2 nanoparticles were added.

This paper examined the effect of two types of nanoparticles-titanium dioxide (TiO2) and montmorillonite (MMT) nanoclay -on the behavior of cement pastes modified with two pozzolanic materials, namely, fly ash (FA) and recycled glass powder (GP). The compressive test was performed to assess the compressive strength; the non-evaporable water content measurement was carried out to study the hydration; and electrical resistivity measurement was conducted to investigate the transport characteristics of the cement pastes. The results indicated that the addition of the nanoparticles improved the compressive strength of the cement paste without GP or FA. It was concluded that the addition of TiO2 nanoparticles resulted in an increased electrical resistivity compared to MMT nanoparticles at late ages. Both TiO2 and MMT exhibited a similar effect on the hydration of the cement pastes.