Figure 3-73: Flowchart.

Flowchart for identifying infilling materials in cracks and voids as applied to CA-058-141. This flowchart from Volume 2 of the guidelines shows how to use petrographic or SEM analysis to determine the cause of an MRD. For the Boron, California site, staining techniques and both scanning electron and petrographic microscope analysis were used and the following conditions were found to be present, which led to the establishment of a cause and effect for each MRD:

• Sulfates were present suggesting a sulfate attack may have occurred;
  
• No chloro-aluminates, calcium hydroxide, calcite, magnesium silicate hydrates, iron oxide or other substances were found to be present, thereby ruling out the possibility of a de-icer attack, an ACR, or possible corrosion of embedded steel; and
• Alkali-silica reaction productions were present; thus, an ASR was possible.

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