Theimpact of sample crushing on the detected porosity of hardened cement pastes bylow temperature calorimetry (LTC) was studied using powder and cylindersamples. Two types of cements, CEM I and CEM III were used to prepare thepastes. A model porous material, MCM-41, was also used in order to investigatesome aspects of the measurement and the evaluation approach. The powder andcylinder samples of the cement pastes were compared in terms of the calculatedice content curves, total pore volumes and pore size distribution curves. For thetwo studied cement pastes, the calculated ice content curves of freezing of thepowder sample differed from that of the cylinder samples, especially for thepaste CEM III. The results indicate that sample crushing changed the poreconnectivity as compared to non-crushed samples. One important differencebetween the powder sample and the cylinder samples of the paste CEM III wasthat the determined maximum ice content in the powder sample was much higherthan that in the cylinder samples, the relatively difference being about 40–50%.However, this kind of marked difference was not found in the paste CEM I. Theobserved difference between the calculated pore volume of the powder and thecylinder samples of the paste CEM III is possibly due to some of the “isolated”pores which, presumably, cannot be fully filled with water in the preparationof the cylinder samples. However, sample crushing makes it possible to saturatethe pores to a greater extent if the crushing contributes to open up the“isolated” pores. Consequently, more pores are detected in the powder samples.The argument that the “isolated” pores have a tendency to be opened up by thecrushing process is supported by results using gravimetric measurements and“dynamic (water) vapor sorption” measurements on powder samples.