Comparison of Sorptometric and Thermoporometric Measurements on Porous Glass and Some Others

The results of surface structure investigations involving the use of thermoporometry and gas-sorptometry on porous glass, silica and a zeolite were compared. The most frequent and the mean pore width were found to be in accordance, but major differences in specific surface were observed. These two measuring methods complement each other, because with gas adsorption a dry sample is investigated, while with thermoporometry a sample immersed in a liquid is investigated. The probe molecules (nitrogen or noble gas and water or benzene, respectively) differ in size. The features of the two methods are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Gravimetric,Volumetric And Calorimetric Studies of The Surface Structure of Portland Cement

Dry cement powder and hardened cement paste were characterised by means of laser granulometry and volumetric measurement of the nitrogen adsorption isotherm at 77 K. Water sorption isotherms at ambient temperature were measured stepwise by means of a gravimetric apparatus. The isotherms show a very large hysteresis loop, reaching down to zero relative pressure, which reflects swelling of the cement gel. Thermoporometric measurements reveal that swelling of that gel consists in water take up within the continuously growing structure; no stable pore structure could be observed. This revised version was published online in August 2006 with corrections to the Cover Date.