Applications of nanotechnology for the sustainable development of cement -based materials

Nanotechnology is a revolutionary discipline in the area of applied science and technology and is expected to have a considerable impact on society. The field of construction materials is no exception. The intrinsically conservative nature of the construction industry might have slowed down the implementation of nanotechnology. It was soon realized however that nanotechnology could facilitate the development of new monitoring systems, new repair methods and even new construction materials.;Three themes were chosen for this thesis based on the application and potential of nanotechnology to enhance the use of the cement-based construction materials for sustainable development.;Theme 1 focuses on the effect of a nano-sized calcium carbonate (CaCO 3) as an accelerating additive for the hydration of cement paste containing high volumes of supplementary cementing materials (SCMs). The conduction calorimetry results showed that the delayed early hydration of ordinary Portland cement (OPC) paste containing high volumes of SCMs was significantly counteracted by the addition of nano-sized CaCO3.;Theme 2 focuses on the synthesis of a highly reactive nano-sized beta-C 2S at low temperatures by a novel technique, referred to as the Sucrose method, used for the first time in the field of civil engineering. The highly reactive nano-sized beta-C2S was successfully synthesized at 600°C and its hydration was significantly faster than that of the commercial beta-C 2S. It was also demonstrated that the mechanical property of the hydrated highly reactive nano-sized beta-C2S was improved.;It is undeniable that more sources of energy will be required worldwide to satisfy a growing population. It is therefore recognized that all the industries are responsible for implementing policies for sustainable development---the ability to meet the needs of the present without depleting the resources for the future.;Theme 3 focuses on the synthesis of a nano-sized calcium hydroxide (Ca(OH) 2) by two methods, the planetary-mill grinding method and the vacuum calcination method in order to tailor the pozzolanic reaction between the nano-sized Ca(OH)2 and metakaolinite. The efficacy of the use of the nano-sized Ca(OH)2 to enhance the pozzolanic reaction with metakaolinite was confirmed.