Sensitivity and uncertainty estimation of cement paste properties to microstructural characteristics using FOSM method

The spatial distribution of microstructures in cement paste affects its mechanical and thermal properties. To evaluate the material properties of cement pastes statistically, sensitivity analysis using the first-order second-moment (FOSM) method is performed. Two random variables, namely porosity and pore continuity, are selected as input variables, and the stiffness and thermal conductivity of cement paste are selected as output variables. The statistical distributions of the input variables are obtained from X-ray micro-computed tomography (CT) images of 64 specimens and responses are estimated by using virtual specimens reconstructed from the data of the real specimens. The uncertainty of the properties when considering two random input variables agrees well with the simulation results based on the micro-CT images of real specimens. It is demonstrated that FOSM analysis with a microstructure reconstruction process can be used as a framework for estimating the sensitivity and uncertainty of material properties as long as the output responses are monotonic and approximately linear to the input variables.