A tribute to Dr. Geoffrey J.C. Frohnsdorff

     Dr. Geoffrey J.C. Frohnsdorff was born in London, England in 1928. He earned undergraduate degrees in mathematics, natural philosophy, and chemistry at St. Andrews University in Scotland. He went on to get a masters degree in physical chemistry from Lehigh University in the US and a doctoral degree in physical chemistry from Imperial College in London. He told me once, with an air of pleasing satisfaction, that he had had a fellowship from the Royal Commission for the Exhibition of 1851, the famous Crystal Palace exhibition, which enabled him to complete his doctoral degree in 1959. After a postdoctoral stint in Canada, at the Royal Military College, and short careers in industry at American Cement Corporation in California and the Gillette Research Institute in Maryland, he joined the National Institute of Standards and Technology, then the National Bureau of Standards, in 1973, retiring as Chief of the Building Materials Division in 2002.

    Geoff was a humble man and told me that in his career, he had had two or three good ideas and the rest of the time he spent “signing bits of paper.” I didn’t tell him at the time, but I thought that was rather an understatement. His “two or three good ideas” included the importance of service life prediction and its corollary, durability, the computer modeling of concrete, and the thesis of this paper, that concrete measurements must become more materials science-based and that experimental and computational materials science need to work together in order to see rapid progress in the science and use of concrete. His main legacy in service life prediction, at present, lies in the contributions of the Polymeric Materials Group at NIST, which has done and continues to do stellar work in putting the service life prediction of polymeric building materials like coatings on a firm materials science basis [3]. Let me focus on two of his ideas that have most directly impacted cement-based materials: computer modeling and materials science.

    I am looking at a paper that Geoff gave me, probably when he was downsizing his office after his retirement from NIST. He told me that, as far as he knew, it documented the world’s first computer model of cement hydration. It is entitled “The Mathematical Simulation of Chemical, Physical and Mechanical Changes Accompanying the Hydration of Cement” [4], and is based on the work Geoff did while he was at the American Cement Corporation at Riverside, California. I have several of his notebooks with printouts of his Fortran code accompanied by extensive flowcharts (Geoff and I always disagreed on flowcharts in general – he loved them and I hate them) dated from April, 1966.

    In 1981, eight years after coming to NIST, Geoff led a successful effort to secure internal, multi-year funding at NIST for cement hydration and eventually concrete modeling. In his first effort, Geoff had tried to model kinetics very carefully, but could not get any 3-D microstructural information, which is needed for fundamental property calculation. This second team effort in 1981 resulted in a C₃S model that could generate a 3-D microstructure upon which one could make a limited number of property calculations [5] but with less detailed kinetics. This model has inspired other work in the Netherlands [6], Japan [7], and Switzerland [8]. The development of various forms of CEMHYD3D and associated computations was the next in this direct lineage [9] and was carried out with the encouragement of Geoff. This model has more complete portland cement chemistry than its predecessors but uses only empirical kinetics in order to be able to rapidly generate realistic 3-D digital-image-based cement paste microstructures that can be used to compute almost any basic measurable physical quantity. The next generation of model development now going on at NIST, called HydratiCA, which also received Geoff’s encouragement after his retirement from NIST, is trying to have both real kinetics and realistic microstructures that can be used to compute any physical property of interest – in other words, a marriage of all the best points of the models to date in the direct lineage from Geoff’s original 1960s model.

    Geoff was trained in physical chemistry and not civil engineering, which gave him a different point of view on materials.  This background and his experience in the industry led him to promote changing the measurements in concrete technology to become more materials science-based. This was done in many ways and I can only mention a few. He was one of the leaders in setting up the original Center for Advanced Cement-Based Materials, a joint effort of Northwestern University, the University of Illinois, the University of Michigan, Purdue University, and NIST. One of the lasting contributions of this center has been to get people and ideas from outside civil engineering, including materials science, involved in research on cement-based materials. Geoff was very active in ASTM for over 30 years, receiving many awards. His two greatest achievements, according to his own opinion, were “the 19-year effort to establish C 1157, the first, albeit imperfect and narrow, performance specification for blended cements…” and “the slow, but continuing movement to build the materials science base for C01 standards.” He was especially proud of the ASTM C01 policy language that he pushed to include, which states that “wherever practical, C01 standards should have a sound basis in materials science.”  All these efforts have gone a long way to improve the materials science basis for the measurements made on cement-based materials.

     I close this section with a picture of Geoff, taken probably when he was in his late 50’s or early 60’s. When I met him in 1988, when I started at NIST, he had just turned 60, so this is how I will probably best remember him. Besides being my boss at NIST, and his influence on me, he actually affected my career even before I came to NIST. When I worked in industry, and became interested in calcium phosphate cements, a special issue of the Philosophical Transactions of the Royal Society of London on hydraulic cements in the 1990’s had an article in it by Geoff and his old friend Jan Skalny [10]. This complete issue,

                                 In memoriam, Dr. Geoffrey J.C. Frohnsdorff, 1928-2006

which I ordered and devoured, helped get me very interested in cements in general, and helped me in my decision to take a gamble on NIST and cement research when I was looking for a new job in 1988. At his retirement lunch in 2002, Geoff and I agreed, in public, that though we disagreed on religion and politics, we were good friends regardless, and we were completely agreed on the role of materials science and computer modeling in concrete science and technology. A more minor point of agreement: my family and I have enjoyed, because of Geoff’s recommendation, the series of books about Biggles, the fictional British aviation pioneer. I will always remember Geoff fondly.

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