Use of strontium isotopes to determine the origin of cement in concretes case examples from New Zealand

Abstract Combined chemical and strontium isotopic analysis has shown that New Zealand cements carry geochemical fingerprints from their raw materials, which can be used to identify them in concrete. This could prove to have a more general application in tracing the origin of cement and identifying the causes of failure in concrete structures. The fingerprinting of cement in concrete is complicated by aggregate leaching, but this can be minimised by using slightly alkaline or neutral EDTA as the solvent in preference to weak mineral acids such as HNO 3 . Although fingerprinting of most New Zealand cements is possible, based on the relative concentrations of Ca, Sr, and Mn, strontium isotopes can add crucial information in certain cases, particularly where limestones of contrasting geological ages have been used as raw materials.