ASTM C1679-17 PDF Download

ASTM C1679-17 is a standard practice that describes the apparatus and procedure for measuring the relative differences in hydration kinetics of hydraulic cementitious mixtures using an isothermal calorimeter. The standard applies to both paste and mortar specimens, including those containing admixtures, supplementary cementious materials (SCM), and other fine materials.

The thermal power curves obtained from the isothermal calorimetry are used to evaluate the hydration profiles of the mixtures during the early period after being mixed with water. These profiles can provide indications of setting characteristics, compatibility of different materials, sulfate balance, early strength development, and the effects of compositions, proportions, and time of addition of materials as well as curing temperature. The standard also mentions that the procedure can be used to measure the effect of chemical admixtures on the cement hydration profile.

However, it is important to note that the isothermal calorimetry results obtained from this practice cannot definitively predict concrete performance either positively or negatively. Concrete testing at planned dosages and temperatures, and at higher dosages, is necessary for extensive verification. The standard also highlights that the isothermal calorimetry is an effective tool for identifying sensitivities and efficiently planning and performing concrete testing.