Determination by nanoindentation of elastic modulus and hardness of pure constituents of Portland cement clinker

The mechanical properties, particularly the elastic modulus and the hardness of the major phases of Portland cements (C3S and alite, C2S and belite, C(3)A, C(4)AF) are measured at the microscopic scale by nanoindentation and at the macroscopic scale by the resonance frequencies technique. At the microscopic scale, the elastic moduli of these phases range between 125 and 145 GPa. The hardness of the calcium aluminate (C(3)A) is around 10 GPa while those of the silicates are lower (8 to 9 GPa). There are no significant differences between the elastic properties of the pure phases (C3S, CIS) and those of their solid solution alite and belite found in industrial clinker. The results found at the macroscopic scale takes into account the bulk porosity of the samples. The elastic moduli of the C3S, C2S, C(3)A phases decrease by about 35% when the porosity decreases by 15%. The elastic moduli obtained at the macroscopic scale, by extrapolation at zero porosity, are in good agreement with the results obtained at the microscopic scale by nanoindentation. (C) 2001 Elsevier Science Ltd. All rights reserved.