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Du er her: DBR > Quantification of early age hydration of Portland cement and pure cement phases

Quantification of early age hydration of Portland cement and pure cement phases

Title:
Quantification of early age hydration of Portland cement and pure cement phases

Type of project:
PhD.-project

Responsible part:
DTU, Dept. of Civil Engineering

Description:
Understanding the process of cement hydration and identifying factors that influence cement performance is of great importance for cement manufacturers worldwide. In cooperation with Lafarge Research Center (France), this project deals with the quantification of early age hydration (up to 7 days after mixing).

In a first step, the hydration of pure cement phases will be studied. Thereafter complexity will be increased by putting together two ore more pure phases two form so-called “synthetic mixtures”. The final goal is to be able to follow the hydration in ordinary Portland cement.

The main approaches used to observe the reaction of the samples include: 
Collection of data on the enthalpy and volume change of the hydration reactions in the samples. Further combination of this data enables deconvolution of the signal from the complex reactions and enables extraction of qualitative and quantitative information about the hydration reactions taking place. A special isochor volumeter is used to measure the volume change in paste samples. It operates at constant 10 bar of pressure and uses a vacuum driven filling system without mechanical stirring. For the isothermal calorimetry a special (vacuum filling, non-stirring) sample holder provides sample treatment comparable to the volumeter.

X-ray diffraction combined with Rietveld data refinement techniques giving quantitative results on the development of both anhydrous clinker phases content and the newly formed hydrate phases over time. The measurement is performed using slices cut from a hydrating cement paste cylinder in regular intervals and, for pre-setting data, in a environment controlled sample chamber.

These two main sources of data are complemented and compared with data acquired by e.g. DTA/TG, solid state 29Si MAS-NMR and scanning electron microscopy.

Project period:
June 2006 – May 2009

Participants:
DTU, Dept. of Civil Engineering

Link:
www.byg.dtu.dk

Relation to the Danish Concrete Counsel focus areas:
1. Efficiency and economics
2. Aesthetics, function, and flexibility  x
3. Environment, work environment, and indoor climate
4. Recruitment, education, and R&D