Our laboratory is investigating the cause of an explosion. I have made extractions of some fragments of concrete and found small amounts of fatty acid esters and starch granules. These are sometimes constituents of explosives. Our question is:

Are these materials ever used as constituents of concrete?

We have not been able to tell whether the materials are concentrated on the surface or distributed throughout the body of the concrete fragments.

These products could be constituents of admixtures used in the concrete when it was mixed. If the construction job records are still available you might be able to track down the trade names of any admixtures used on the job and determine whether they were used in the part of the structure you are examining. A conference with the manufacturer or manufacturers might reveal whether any fatty acid ester or starch was being used in their admixtures at the time of construction.

Editorial Comment:

It has been brought to our attention that there are additional possible sources of fatty acids used with or in concrete: form release agents and so-called waterproof cements, either of which may contain fatty acids or fatty-acid derivatives. It could be added that if a concrete wall were washed down with soap and water it would probably be coated with residual salts of fatty acids, even though the wall were thoroughly rinsed as part of the cleaning process.