1. Concrete and Construction Chemistry Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
2. Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, U.K.
3. School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, U.K.
4. Laboratory of Construction Materials, EPFL, 1015 Lausanne, Switzerland
5. Institute for Building Materials, ETH Zurich, 8093 Zurich, Switzerland