The quantitative evaluation of the water/cement ratio using fluorescence microscopy

The water/cement ratio is a prime parameter in determining a concrete's strength and durability. The British Standard method for determining the ratio in hardened concrete involves the separate determination of the original cement and water contents. It is acknowledged that the accuracy of this method is strongly dependent upon the availability of separate samples of the original cement and aggregates. A direct method using thin-section optical microscopy has been introduced in Denmark but the method described here uses reflected light fluorescence microscopy. Results are presented for hardened cement pastes and mortars, together with some preliminary results for concrete.