Home institution University of Maribor Faculty of Civil Engineering Slovenia

1. Education and Culture Lifelong Learning Programme ERASMUS Assist.Prof.Dr. Lucija Hanžič LECTURE 1 Application of neutron radiography for the study of moisture in concrete www.fg.uni-mb.si/lucija/presentations/2008sakarya-lecture1.ppt 14 – 18 April 2008 Host institution Sakarya University Technical Education Faculty Turkey Home institution University of Maribor Faculty of Civil Engineering Slovenia

2. Assis.Prof.Dr. Lucija Hanžič Application of neutron radiography for the study of moisture in concrete Physical causes Freezing and thawing Deterioration due to moisture Chemical causes Transport media for deleterious substances 2/6 University of Maribor, Faculty of Civil Engineering Moisture in concrete Concrete is one of the most important construction materials. During exploitation concrete is often subjected to moisture which is the key factor of different deterioration processes. Figure 1. Use of concrete in structures. Cement matrix How to observe the movement of moisture in concrete? • Hydrated cement • Gel water • Fine aggregate • Pores Coarse aggregate Figure 2. Microstructure of concrete. Figure 3. Deterioration of concrete due to freezing in the presence of moisture.

3. Assis.Prof.Dr. Lucija Hanžič Application of neutron radiography for the study of moisture in concrete Animation 1. Bohr-Rutherford atomic model and simplified spherical atomic model www.voyagesolarsystem.org, 28.03.2008. Protons (p) Nucleus Neutrons (n) ATOM Electron shells Electrons (e) 3/6 University of Maribor, Faculty of Civil Engineering Structure of solid materials Atom diameter ≈ 105 Nucleus diameter Neutron interactions Scattering(n, n) – neutron strikes the nucleus and then the neutron reappears. It is most likely that the neutron will reappear in the forward direction. Animation 3. Elastic scattering. Radioactive capture (n,γ) – neutron is captured by the nucleus and γrays are emitted. Animation 4. Radioactive capture. Neutron producing reactions(n, 2n) and (n, 3n) Animation 2. Atomic arrangement in crystalline material and movement of neutron through solid material. Charged particle reactions(n, p) and (n, α) Fission

4. Assis.Prof.Dr. Lucija Hanžič Application of neutron radiography for the study of moisture in concrete 4/6 University of Maribor, Faculty of Civil Engineering Basic principle of NR Table 1. Cross-sections for thermal neutrons of selected chemical elements. Extent to which neutrons interact with given matter is defined as cross-section (σ) and gives the number of interactions per second (Nint/t) for with one nucleus per unit intensity of the beam (Φ0= N/St). Concrete is composed mainly of CaO, SiO. Al2O3 and Fe2O3 and is rather transparent for neutron beam. When passing through water neutron beam is attenuated to a large degree because of H atoms. Degree of attenuation depends on the thickness of water layer. Φ0 Φ Animation 5. Attenuation of neutron beam due to elastic scattering. Concentration of water in concrete specimen (cw) is a function of specimen thickness (d) and ratio between detected (Φ) and initial (Φ0) beam.

5. Assis.Prof.Dr. Lucija Hanžič Application of neutron radiography for the study of moisture in concrete Figure 4. Research nuclear reactor Triga MARK II at Institute “Jozef Stefan”, Ljubljana (a) vertical cross-section and (b) thermal column. T. Nemec, Determination of Hydrogen with Neutron Radiography, PhD thesis, Universityof Maribor, Maribor, 2002. Figure 5. Analysis of NR images in TINA 2.10g computer application (Isotopenmeßgeräte GmbH, 1993): (a) visual determination of liquid front and measurement of its height and (b) determination of liquid front using PSL (Photo-Stimulated Luminescence) profiles. L. Hanzic, Capillarity in concrete, PhD Thesis, University of Ljubljana, 2005. 5/6 University of Maribor, Faculty of Civil Engineering Method (b) (a)

6. Assis.Prof.Dr. Lucija Hanžič Application of neutron radiography for the study of moisture in concrete 6/6 University of Maribor, Faculty of Civil Engineering Further reading El-Abd A.E.-G., Czachor A., Milczarek J.J., Pogorzelski, 2005. Neutron radiography studies of water migration in construction porous materials, IEEE Trans. Nucl. Sci. 52 (1), 299-304. Harms A.A., 1977. Physical processes and mathematical methods in neutron radiography, At. Energy Rev. 15 (2), 327-359. Hoff W.D., Taylor S.C., Wilson M.A., Hawkesworth M.R., Dale K., 1996. The use of neutron radiography to monitor water content distributions in porous construction materials, Proc. 5th Word Conferance on Neutron Radiography, Deutsche Gesellschaft für Zerstörungsfreie Prüfung, Berlin, 594-601. Justnes H., Bryhn-Ingebrigtsen K., Rosvold G.O., 1994. Neutron radiography: an excellent method of measuring water penetration and moisture distribution in cementitious materials, Adv. Cem. Res. 6 (22), 67-72. Kobayashi H., Satoh M., 1999. Basic performance of a neutron sensitive photostimulated luminiscence device for neutron radiography, Nucl. Instrum., Methods Phys. Res., Sect. A, Accel. 424, 1-8. Lamarsh J.R., 1977. Introduction to Nuclear Engineering, Addison-Wesley Publishing Company, Inc., Reading. Nemec T., Rant J., Apih V., 1999. Quantitative measurements of moisture transport in building materials by quasi-real-time neutron radiography, Insight 41 (7), 449-452. Rauch H., Zeilinger A., 1977. Hydrogen transport studies using neutron radiography, At. Energy Rev. 15 (2), 249-290. von der Hardt P., Roettger H., eds., 1981. Neutron Radiography Handbook, D. Riedel Publ. Co., Dordrecht.