Statistical concept of the ``weakest link'' in estimating strength and defects of chemically active composite materials

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.