Dr. Roberto J. Torrent is a researcher, consultant and partner of Materials Advanced Services Ltd. He held positions at the National Institute of Industrial Technology and Portland Cement Institute (Argentina), as well as at Holcim Technology Ltd. (Switzerland). For thirty years he has been directly involved in durability testing of a large variety of concretes, both in the lab and on site. In the 90s he invented the Torrent NDT Method for measuring air-permeability. He is a RILEM Honorary Member.

Dr. Rui Neves was formerly a researcher at the National Laboratory for Civil Engineering (LNEC-Portugal). Currently he is Professor in the Structures and Geotechnics Division at Barreiro School of Technology, Polytechnic Institute of Setúbal, Portugal. His research efforts are mainly devoted to service life of reinforced concrete structures, with special emphasis on investigating and testing the permeability of concrete and rocks. He has carried out relevant consulting activity within the frame of concrete quality control, as well as inspection and appraisal of reinforced concrete structures.

Dr. Kei-ichi Imamoto is a graduate of Tokyo University of Science, Japan. He performed research at Tokyu Construction Co. Ltd. for nine years and is now Professor at Tokyo University of Science. He received the Young Researcher`s award from AIJ (Architectural Institute of Japan) in 2008, and prizes from Japan Society for Finishing Technology, Japan Concrete Institute and Suga Weathering foundation. He is very active in durability testing and service life assessment of concrete structures.

1. Durability Performance of Concrete Structures. 2. Permeability as Key Concrete Property. 3. Theory: Concrete Microstructure and Transport of Matter. 4. Test Methods to Measure Permeability of Concrete. 5. 'Torrent' NDT Method for Coefficient of Air-Permeability. 6. Effect of Key Technological Factors on Concrete Permeability. 7. Why Durability Needs to be Assessed on Site? 8. Why Air-Permeability kT as Durability Indicator? 9. Service Life Assessment Based on Site Permeability Tests. 10. The Role of Permeability in Explosive Spalling Under Fire. 11. Real Cases of kT Test Applications on Site. 12. Epilogue: The Future. Appendix A. Transport Test Methods Other Than Permeability. Appendix B. Model Standard for Measuring the Coefficient of Air-Permeability kT of Hardened Concrete.

This text provides insight into the permeability of concrete, moving from theory to practice, and includes over twenty real cases. It stresses the importance of site testing for a realistic durability assessment and details the 'Torrent Method' for non-destructive measurement of air-permeability.