The measurements were performed during the summer of 1999, when D.P. Bentz was a visiting professor at the Department of Structural Engineering and Materials, DTU, funded by the Knud Hojgaard Foundation. D.P. Bentz would also like to acknowledge fruitful discussions with Dr. Daniel Quenard of Centre Scientifique et Technique du Batiment, Grenoble, France and to thank his wife, Janet Carey-Bentz, for the idea of using the Lego blocks as sample holders. A thorough review of the paper by Dr. Nicholas Carino (Building and Fire Research Laboratory, NIST) is greatly appreciated.