Flaws alumina-based ceramics

L. M. Braun, S. J. Bennison, and B. R. Lawn, Objective Evaluation of Short-Crack Toughness Curves Using Indentation Flaws Case Study on Alumina-Based Ceramics, J. Am. Ceram. Soc., 75[11], 3049-3057 (1992). 

Surface flaws are common in optical fiber because of the processing technique used for the fabrication of fused-silica fibers. They are also very common in other ceramic fibers such as alumina-based or silicon carbide-based fibers. Airborne particles as well as other elements tend to attach to the surface of the fiber during process or handling. 

Concrete is a particulate composite of stone and sand, held together by an adhesive. The adhesive is usually a cement paste (used also as an adhesive to join bricks or stones), but asphalt or even polymers can be used to give special concretes. In this chapter we examine three cement pastes the primitive pozzolana the widespread Portland cement and the newer, and somewhat discredited, high-alumina cement. And we consider the properties of the principal cement-based composite, concrete. The chemistry will be unfamiliar, but it is not difficult. The properties are exactly those expected of a ceramic containing a high density of flaws. 

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