Abstract
Estimation of physical and mechanical and structural parameters of chemically active composite materials of considerable volumes based on properties determined for their elements of volume is discussed. Hardening cement-concrete compositions are a classic example of such materials. Experimental data analysis shows that the statistical model of the ``weakest link'' gives a reasonable description of the brittle fracture process. This approach enabled to obtain a reasonable estimation of strength of structure of a considerable size (volume) based on the measured strength of its individual element. Combined use of the statistical concept of the ``weakest link'', non-destructive method of control, concepts of ``apparent'' structures and activation energy for the formation of structure enables the estimation of parameters of ``apparent'' defects and their stress intensity factors. The obtained results show that the actual strength of cement-concrete composition is by several digits less as compared to theoretical strength based on measuring its total porosity.