HYDRATION AND EARLY-AGE STRENGTH MEASUREMENT OF CONCRETE USING NUCLEAR MAGNETIC RESONANCE (NMR)

A new nondestructive technique for monitoring the hydration process of cement within concrete and measurement of the compressive strength of concrete is presented. The technique called the Nuclear Magnetic Resonance (NMR) has so far been primarily used in the fields of chemistry and medicine. Its application to construction materials has been very limited or nonexistent. In this study, NMR is used to monitor the. hydration of cement paste in concrete with two different water cement ratios. The first objective of this study was to distinguish between the amounts of remaining free water, and water consumed in the hydration process during the 28 days monitoring period. The second objective was to relate the compressive strength of concrete to NMR signals. A number of standard compression tests were performed in parallel with the NMR tests. Correlation of the responses from nondestructive tests with NMR and those of standard compression tests indicated almost a linear relationship.