Synthetic tobermorite 97 Hydrothermally reacted cured mixtures of limebentonite Room cured mixtures of lime-bentonite Infrared Spectroscopy Pure compounds Dry mixtures of lime-bentonite Room cured mixtures of lime-bentonite Calcitic lime plus bentonite Dolomitic monohydrated lime plus bentonite Dolomitic dihydrated lime plus bentonite Hydrothermally reacted cured mixtures of limebentonite Calcitic lime plus bentonite Dolomitic monohydrated lime plus bentonite Dolomitic dihydrated lime plus bentonite Electron Probe Analysis Summary of Results 139 DISCUSSION 145 Calcium Aluminate Hydrates 145

No abstract

Calcium aluminate and calcium silicate hydrates were formed in mixtures of bentonite with water and various types of lime which had been sealed and cured for up to three years at 23°± 2°C and 100% relative humidity. Methods of analysis were X‐ray diffraction and electron microscopy. Hydrothermal treatment of the cured mixtures at 170°C for 12 hr produced well‐crystallized tobermorite with apparent lattice substitution of aluminum. The same result was obtained by hydrothermal treatment of identical uncured mixtures.

Mixtures of three types of lime, bentonite, and water were analyzed by infrared spectroscopy after three years of reaction at 23°C under conditions approaching 100% rh and after hydrothermal reaction at 40", 80", and 170°C. The procedure was effective for analysis of complex mixture components. New compounds identified in the 23°C mixtures were calcium carbonate as well as hydrates of calcium silicate and calcium aluminate. Tobermorite was identified in a11 170°C mixtures, with indications of serpentine and possibly chlorite in mixtures containing dolomitic lime, particularly the monohydrated form. Remnants of initial components not used in the reaction were also noted. Implications for analysis of compound structures are discussed, with particular reference to lattice substitution of aluminum and magnesium.