Figure 3-19

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Flowchart for assessing the condition of the concrete aggregates as applied to the Spearfish, South Dakota site. This flowchart from Volume 2 of the guidelines shows how to examine the coarse and fine aggregate structure and type to determine if the paste condition should be evaluated. For the Spearfish, South Dakota site, examination of the coarse and fine aggregate structure and determination of the coarse and fine aggregate type showed the following conditions to be present and led to the examination of the paste condition:

• Coarse aggregates were cracked and the cracks extended into the paste;
• The concrete was located in a freeze-thaw susceptible climate and had freeze-thaw susceptible aggregates suggesting possible aggregates freeze-thaw distress;
• Cracks were filled, which led to the need to identify the in-filling material;
• Fine aggregates were not cracked;
• Reaction rims were visible;
• Secondary in-filling of cracks and or voids was occurring, which led to the need to identify the in-filling material; and
• Aggregates were softening and were made from an ACR susceptible material; thus, an ACR might have occurred.