When cement powder is mixed with water, a series of complex chemical reactions and physical changes takes place. The final result – cement paste – is a complex, multi-component material with a variable and porous composition. Cement is, moreover, a “live” material – throughout its life, even dozens of years after hardening, its structure continues evolving, undergoing physical and chemical changes.
Amongst the different components of the cement matrix, the most important is undoubtedly that known as C-S-H gel. C-S-H gel, acronym for calcium silicate hydrate, represents 70% of the matrix and is mainly responsible for the cohesion and mechanical properties of the material. Nevertheless, despite its importance, many aspects of the gel, including its exact composition, are still unknown.
Simulation at an atomic scale
The application of the atomistic simulation enabled Mr Manzano to understand the properties and characteristics of this gel. The atomistic simulation methods enable the properties and the behaviour of the materials to be studied at a level of the interactions amongst the atoms making them up. Knowledge of cement at an atomic scale will facilitate the design of modifications that will enhance performances and properties
After four years of research, Mr Manzano has found, amongst other things, that there is a clear relation between the mechanical properties of C-S-H gel and the internal structure of the nanoparticles that it is made of. C-S-H gel is made up of colloidal nanoparticles that aggregate in various ways in order to make the material. The manner in which these nanoparticles are ordered amongst each other is probable the factor that most influences the mechanical properties of the cement. The closer together they are and the less space between them there is, the more dense is the C-S-H gel and the better its mechanical properties. But this is not the only factor to be taken into account. The internal structure of each one of these particles also affects the total.
Each particle is formed by laminas of calcium oxide surrounded by chains of silicates of various lengths. We have shown that, the longer these silicate chains, the individual properties of each particle improve and, at the same time, the overall qualities of the C-S-H gel are improved. Based on these results, Mr Manzano concluded that the mechanical properties of the cement can be enhanced by 30% if, during its hydration, the formation of longer silicate chains and more compact C-S-H gels is boosted. An improvement of this magnitude would have great impact on the cement industry which, in 2008, produced almost 3,000 million tons of cement. An enhancement of 30% in the mechanical properties implies approximately 30% less cement in order to achieve the same resistance in a building. Thus, the production of cement is reduced and, as a consequence, emissions of CO2 to the atmosphere likewise.
Despite the research already carried out, there are still many aspects of cement to be studied, in order to achieve improvements in the material that will have an impact on a sector as important as construction.
Amaia Portugal | alfa
An innovative high-performance material: biofibers made from green lacewing silk
20.01.2017 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Treated carbon pulls radioactive elements from water
20.01.2017 | Rice University
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences