The secret of nanoparticle packing in cement
Jan 23, 2013
Construction site, general
Cement production is responsible for 5 % of carbon dioxide emissions. If we are to invent a "green" cement, we need to understand in more detail the legendary qualities of traditional Portland cement. A research group partly financed by the Swiss National Science Foundation (SNSF) is tackling this task.
Discovering the perfect composition of Portland cement, the most common type of cement, was the result of years of experience as well as repeated trials and errors. Emanuela Del Gado, SNSF professor at the Institute for Building Materials of the ETH Zurich, explains that its success is the result of two key factors: its legendary hardness and the availability of its constituent elements.
5 % of carbon dioxide emissions
The flipside of the coin: its production requires burning calcium carbonate. This process is responsible for approximately 5% of all carbon dioxide emissions or the equivalent of the entire 2007 emissions of India. But a more sustainable recipe for cement has to meet high standards both in terms of material hardness and accessibility to raw materials.
Because of the massive ecological impact of cement production, various research groups worldwide are trying to understand why the mixture of this powder and water sets to such hardness.
Different densities at the nano level
Researchers of the Massachussetts Institute of Technology (MIT) have concentrated on studying the behaviour of concrete at the nano level. In their experiments, they used an instrument capable of applying mechanical stress at the sub-micro level. As a result, they were able to show that densities vary strongly from one measuring point to the other at this scale. But they were not able to explain why.
This is where physicist Emanuela Del Gado enters the scene. She takes a special interest in amorphous materials whose constituents combine in a disorderly manner. Her studies of such materials focus on the nano level. "It is at this level and not at the atomic level that certain material properties are revealed. This also applies to hydrated calcium silicate, a major component of cement which plays an important role in the setting process," she explains.
Packing particles of different sizes
The researchers first developed a packing model of hydrated calcium silicate nanoparticles. They then devised a method for observing their precipitation based on numerical simulations. This approach has proven successful (*). "We were able to show that the different densities on the nano scale can be explained by the packing of nanoparticles of varying sizes. At this crucial level, the result is greater material hardness than if the particles were of the same size and it corresponds to the established knowledge that, at macroscopic level, aggregates of different sizes form a harder concrete."
Until today, all attempts to reduce or partially replace burnt calcium carbonate in the production of cement have resulted in less material hardness. By gaining a better understanding of the mechanisms at the nano level, it is possible to identify physical and chemical parameters and to improve the carbon footprint of concrete without reducing its hardness.
(*) E. Masoero, E. Del Gado, R. J.-M. Pellenq, F.-J. Ulm, and S. Yip (2012). Nanostructure and Nanomechanics of Cement: Polydisperse Colloidal Packing. Physical Review Letters. DOI: 10.1103/PhysRevLett.109.155503
(available in PDF format from the SNSF; e-mail: com@snf.ch)
Contact
Prof. Dr. Emanuela Del GadoInstitut für Baustoffe
ETH Zürich
CH-8093 Zürich
Tel.: +41 44 633 37 44
E-mail: delgado@ifb.baug.ethz.ch
More News and Articles
Aug 28, 2024
News
ITpipes Secures $20M to Transform Water Infrastructure Management
ITpipes announced it has secured $20 million in equity financing from Trilogy Search Partners and Miramar Equity Partners.
Known for its trusted and user-friendly platform, ITpipes …
Aug 26, 2024
News
Professor Dr.-Ing. Dietrich Stein
With deep sadness we announce the loss of our founder and partner Prof Dr Dietrich Stein at the age of 85.
Engineers around the globe are thankful for his dedication to the inventions in the fields of sewers, …
Aug 26, 2024
News
PPI Releases New Installation Guide for PE4710 Pipe
PPI’s MAB-11-2024 Covers HDPE Water Pipelines Up to 60-in. Diameter and 10,000-ft Long Pulls
Developed by the Municipal Advisory Board (MAB) – and published with the help of the members of the …
Aug 23, 2024
News
Faster wide-scale leak detection now within reach
Mass deployment of connected leak loggers is being made possible by the latest technology, writes Tony Gwynne, global leakage solutions director, Ovarro
Water companies in England and Wales are …
Aug 21, 2024
News
Kraken awakens customer service potential in water
The innovative customer service platform Kraken has made a successful transfer from energy to water. Ahead of their presentation at UKWIR’s annual conference, Portsmouth Water chief executive …
Aug 19, 2024
News
Predicting the toxicity of chemicals with AI
Researchers at Eawag and the Swiss Data Science Center have trained AI algorithms with a comprehensive ecotoxicological dataset. Now their machine learning models can predict how toxic chemicals are …
Aug 16, 2024
News
Goodbye water loss: Trenchless pipe renewal in Brazil
Pipe renewal in Brazil
How do you stop water loss through leaks in old pipe systems without major environmental impacts and restrictions? The answer: with trenchless technology, or more precisely …
Aug 14, 2024
Article
Impact of high-temperature heat storage on groundwater
In a recently launched project, the aquatic research institute Eawag is investigating how the use of borehole thermal energy storage (BTES) affects the surrounding soil, the groundwater …
Aug 12, 2024
News
Watercare completes East Coast Bays sewer link
Watercare has successfully finished the final connection on the East Coast Bays link sewer at Windsor Park in New Zealand.
Much of the East Coast Bays sewer link was installed using horizontal directional …
Aug 09, 2024
Article
Innovative water solutions for sustainable cities
Cities need to become more sustainable and use their water resources more efficiently. Managing water in local small-scale cycles is one possible solution. A new white paper by Eawag, the University …
Aug 07, 2024
Article
How digital technologies contribute to universal drinking water
Digital water technologies have an important role in ensuring universal access to safe drinking water by 2030, that is according to a new report from the World Health Organisation. …
Aug 05, 2024
News
Knowledge transfer on sustainable water infrastructure in India
India’s fast-growing cities need an efficient infrastructure for water supply and wastewater disposal. A research cooperation, is therefore supporting the development of a sustainable …
Contact
Swiss National Science Foundation (SNSF)
Wildhainweg 3
3001 Bern
Switzerland
Phone:
+41 31 308 22 22
Fax:
+41 31 301 30 09