Texture of calcium hydroxide near the cement paste-aggregate interface

Abstract Several researchers have been using an X-ray diffraction technique to examine the orientation of calcium hydroxide crystals at the interface between cement paste and aggregate. Recently, however, the use of X-ray diffraction for this purpose has been called into question because the goniometer sweeps through only a single arc, thus missing any crystals which are not oriented with either a (0001) plane or a (10 1 1) plane parallel to the interface. This paper describes the degree of preferred orientation of calcium hydroxide crystals using pole figures. The results confirm the validity of the X-ray diffraction technique and provide new information about the nature of the cement paste-aggregate interface.