The Genesis of Concrete project started within the CSHub with the aim of driving the development of the new generation of "green" cement-based materials. Due to the present climate scenario, it is of vital importance that the cement and concrete industry implement environmentally friendly solutions for the production of a better material taking into account that cement production is responsible for about 5% of the anthropogenic CO2 emissions. Any small improvement on its performance could induce huge environmental benefits.
We wish to develop a bottom-up approach as a novel and fresh point of view to cement poromechanics, contrary to classical engineering top-bottom approach combining both nano-scale simulations and experiment. This is the Genesis of Concrete project that tackles the most important challenges in cement research, such as the clinker hydration, the formation of the C-S-H gel, and cement paste cohesion, etc… Covering all these areas is necessary to make a real impact in cement performance, as material properties do not rely only in one of these aspects, but in all of them. We strongly believe that understanding the physical and chemical processes that take place in cement at the atomic and nanoscale will lead us to conceive the necessary modifications to design a material with better final properties, reducing at the same time its environmental footprint.
The ability of the clinker phases to react with water governs the release rate of ions to the solution, and hence, the formation of the cement paste. It is well known that the clinker phases present very different hydraulic activity, but the origin of this difference is not clear. In the Genesis of Concrete project, we take advantage of ab-initio simulations to study the intrinsic reactivity of the clinker phases and the effect of impurities in it. We aim at being able to suggest the necessary modifications of clinker formulation to accelerate or delay the dissolution reaction of clinker phases, in order to achieve a technological advantage from the clinker production process.
The large number of coupled chemical reactions during the formation of the C-S-H gel and its heterogeneity make difficult a proper characterization of its nucleation and growth mechanism. Our team goal is to study how the C-S-H gel is formed from the electrolyte pore solution, using reactive Molecular Dynamics and Monte Carlo approaches. We will obtain the growth kinetics of the C-S-H gel.
The key process at the microscale is the percolation of the colloidal C-S-H gel nanoparticles. Using a variety of atomistic simulation methods combined with advanced statistical physics (meta-dynamics approaches), we aim to explore these forces, which will lead to understanding the complex processes that take place in the cement paste, i.e. setting, creep, and shrinkage.
Contrary to previous works, we will use computational simulation not only to explain experimental facts, but also to predict and suggest beneficial changes for different aspects of cement technology. Nevertheless, an experimental effort is always necessary to ensure the validity of the results and their transferability to real conditions. This will be done using the necessary experimental techniques for each specific problem, such as solid-state NMR, SANS, nanoindentation, WDS, sorption measurements, etc. Furthermore, ab-initio simulation of solid state NMR for an accurate interpretation of the experimental data is included within the validation methods.
Life Cycle assessment (LCA) can be used to quantify the environmental performance of buildings and pavements. This research analyzes the life cycle performance of residential buildings, commercial buildings, and highway pavements, for several climatic regions of North America. By considering all phases of use, from construction through demolition, areas of good environmental performance can be identified, as well as areas for improvement.