Influence of nano-TiO2 on mechanical property and hydration characteristic of cement high volume of fly ash system
The influence of nano-TiO2 (NT) on the mechanical properties and hydration characteristics of a cement high-volume fly ash (CHVFA) system were studied in this paper. The compressive strength of CHVFA mortars was tested with different FA and NT contents. Results show that the addition of NT increases the strength significantly, while the degree of enhancement wanes with increasing length of the curing. The mechanism of NT on properties of the CHVFA system was analyzed by X-ray diffraction (XRD), differential scanning calorimetry-thermogravimetry (DSC-TG), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). The results reveal that the addition of NT accelerates the hydration of cement and fly ash significantly, but the promotion effect is delayed along with the curing age, thus lessening the facilitating role of NT on the compressive strength of CHVFA mortars.
1 Introduction
China is a coal-fired country. Both at present and for a rather long time to come, coal is and will remain the country’s main source of energy. Fly ash (FA) is an inevitable product of coal-fired power generation, with every 4 tons of coal consumption producing 1 ton of FA. In 2015, according to estimates, FA output in China reached 620 million tons, making it the highest in the world [1]. If such a large amount of solid waste is not put to some rational use, it amounts to a great waste of resources, pollutes the environment, consumes large swathes of farmland and affects the...
