Interpretation of Clinkers

Consequently, instead of a chapter organization based primarily on genetic sequence (see Hofmanner, 1973 Chromy, 1974 Butt and Timashev, 1974 Ono, 1981, 1995 Chromy, 1982 and Gartner, 1985), the observations and interpretations in this chapter are listed first with some of the relatively large-scale features of clinkers and then, for the most part, according to phase abundance. Rather than in a lengthy narrative survey of interpretive details of clinker phases, stated by various authors in many published papers, the information is presented in tabular form. Table 7-1 presents, in a double column, a list of (a) clearly recorded observations on the left and (b) verbatim published interpretations, associations, or correlations on the right. This survey is not a critical review. 

Seldom does a single observation of a particular microscopic feature provide sufficient evidence to warrant a widely applicable interpretation. Most interpretations given herein represent conclusions drawn 

Unfortunately, some interpretations stated by different authors in the table are contradictory and the reader is left to his or her experience to determine the correct statement. Additionally, some observations may have more than one correct interpretation, that is, multiple causes. Some of the stated correlations may not be cause and effect relationships. Furthermore, some of the referenced work appears less than systematic. Such problems point out the need for research, and, indeed, it is hoped that the contents of this publication serve to stimulate scientific cement research, particularly quantitative microscopy with a statistical approach, using techniques that group and characterize the sets of observations and genetic conditions. 

The photographs in this section are illustrations of clinkers examined and interpreted by this writer, with emphasis on the use of Ono s interpretive table (Table 6-1). It is important to note that individual photographs may not depict all the microscopic features normally associated with the stated interpretation of kiln conditions, the interpretation having been drawn from the results of several techniques of examination and study of several clinkers in the sample. Designations such as 42.8 MPa in the photomicrograph captions indicate reported 28-day mortar-cube strength. 

Evenly distributed phases idiomorphic alite rounded belite finely differentiated matrix scarce, small, free-lime crystals Optimized manufacturing conditions correcf chemical composition of raw feed, well mixed, no particles too coarse, satisfactory maintenance of sintering and cooling temperatures (Hofmanner, 1973) 

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S. Brown deserves special recognition for his observational skills and interpretive acumen. Brown worked for Lone Star Research Laboratory in Hudson, New York, in the 1930s and in 1940 joined the research staff at the Portland Cement Association, where he spent approximately 25 years in cement and concrete investigations. Most of his scientific efforts were dedicated to the microscopical interpretation of clinker burning, cement hydration, and concrete deterioration. An unpublished report (Brown, 1936) contains the following interesting observations ... 

Also among the many major historical contribu tions in clinker microscopy are the works of Parker and Nurse (1939) Taylor (1943) Gille (1955) Kramer (1960) Nurse, Midgley, and Welch (1961) Midgley (1964) Butt and Timashev (1974) and others. Most of these authors are mentioned again in Chapter 7, Microscopical Interpretation of Clinkers. ... 

Interpretations of clinker phases in terms of burning conditions are listed in Chapter 7, and discussed to a limited extent below. 

Unfortunately, some of the observations and interpretations presented in Chapter 7 ("Microscopical Interpretation of Clinkers") do not appear to be founded in systematic experimental design or statistical analysis. Statistical measures to determine the degrees of correlation and association of the observations, and their relationship to the various physical and chemical causal factors of the production process, are essential and urgently needed for several very important reasons ... 

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