INFRARED SPECTROSCOPIC INVESTIGATION OF CONCRETE ADDITIVES

Summary Rapid simple IR spectophotometric methods were developed for the identification and classification of concrete additives, suitable for the replacing of earlier time-consuming more expensive methods. Location and contour of spectral bands, further the relative intensities of a few characteristic bands were used for identification. Investigations discussed in this paper form a part of research work, undertaken with the aim to increase the use of concrete additives in Hungary, with special regard to economy of material and energy by their application. Knowing the IR transmission properties of various additives containing known active substance, our object was to identify the active substances of unknown additives, and to predict on the basis of these properties, their expected concrete technological effect. The study of these effects (setting time, consistency, solidification and shrinkage modification) requires time­ consuming and expensive measurements, which motivated the development of a simple, rapid method, giving reliable results. From the location, contour and relative intensity of the IR absorption bands of the additives the type of the additive, and in most of the cases the additive itself could be identified in our work.