Abstract
The fracture toughness of Ocala chert, as measured with short rod specimens and with the microhardness indenter, decreases to 60% of its original value as a result of heat treatment to 500° C while the elastic modulus increases 22%. The change in fracture toughness is associated with a transition from crack propagation around particles in the porous boundaries of densely packed zones in the chert to propagation through the zones. The transition is related to an increase in particle/particle bonding within the porous boundaries. Consolidation of a silica gel in the boundary regions, which resulted in a loss of water of 1.12% by weight, is apparently responsible for the increased bonding.
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Beauchamp, E.K., Purdy, B.A. Decrease in fracture toughness of chert by heat treatment. J Mater Sci 21, 1963–1966 (1986). https://doi.org/10.1007/BF00547934
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DOI: https://doi.org/10.1007/BF00547934