Materials for Construction
Responsable : Paul Bowen
Cement is one of the most widely used materials of our time and as such its production is responsible for 5 – 8 % of yearly man-made global CO2 emissions (see nanocem website). Research directed at increasing cement mechanical properties and durability which might ultimately lead to a decrease in cement consumption, and consequently CO2 emissions, is therfore of great importance. Many of the questions within cementitous systems, such as colloidal behavior of the pre hydrated cement paste and the properties of the great number of interfaces present in the cement paste as well as in the hydrated cement, are very similar to the questions studied in other areas of powder technology. Consequently the two areas of cement research at LTP are concerned with these topics:
Superplasticizers are aided to cement suspensions in order to enhance the flowability and thus the workability of the pre-hydrated mix. How these superplasticizers change the particle interactions in the mix and increase the flowability is being studied at LTP.
There is still a lot of unknowns about the two main phases in hydrated cement: portlandite and C-S-H. For portlandite the main open question is how different ions in solution will interact with portlandite surfaces and thus influence the growth of the phase. For C-S-H the atomic structure itself is not fully known. At LTP atomistic simulation techniques are used to study these questions.