Quarry waste fines and eggshells are unavoidable wastes which relentlessly contribute to environmental load and pollution. Although a number of studies have suggested various methods for recycling, these wastes remain underutilized due to some technical constraints. In addition, no study has yet been explored on the possibility of combining quarry waste fines (QWF) and eggshell powder (ESP) for tobermorite synthesis. Tobermorite is the main component which primarily provides strength to the autoclaved aerated concrete products. For this purpose, this study seeks to evaluate the potential of QWF- ESP mix at 10%, 15% and 20% amounts of cement, respectively. The XRF, XRD, and TGA–DTA techniques were used to characterize the waste materials while physical and mechanical property tests and XRD analysis were performed on the autoclaved samples. It was found that QWF contains 53.77% SiO2, while ESP contains 97.8% CaO which are key components for tobermorite synthesis. This study also revealed that the mixture with only 10% cement has the highest compressive strength among the QWF-ESP samples. Furthermore, the formation of tobermorite in the samples was confirmed through XRD analysis. Hence, the hydrothermal curing of QWF –ESP can be further developed to produce functional tobermorite – bearing materials.

The main objective of this work is to study the effects of carbon nanotubes (CNT) on the strength and electrical properties of cement mortar. Molecular dynamic simulations (MDS) were carried out for the mechanical and electrical properties of the cementitious composite and the associated mechanisms. To model the atomic structure of the Calcium-Silicate-Hydrates (C-S-H) gel, tobermorite 11Å was chosen. Single-walled carbon nanotubes (SWCNTs) embedded in tobermorite structure were tested numerically. In particular, the effect of the concentration of CNT in cement paste was studied. An innovative experiment of electrical characterization of a cementitious composite of carbon nanotubes has been developed.

Due to the severe environmental impact of the CO2 emissions associated with the production of Ordinary Portland Cement (OPC) and the increasing demand for this commodity material, the development of alternative products has become a global concern. One alternative to OPC, or alitic-based clinkers, are amorphous-wollastonitic low calcium hydraulic binders (AWLCs). This new class of hydraulic binders, described in the literature for the first time in 2015, may significantly reduce the CO2 emissions associated with its production, resulting from its lower calcium content, but also from the fact that its production technology can be fully electrified. In this paper it is provided a state-of-the-art review, providing a comprehensive description on the latest research, summarizing both the physico-chemical and mechanical characteristics for this type of hydraulic binders, as well as possible routes for its production at an industrial scale.