Analysis Of Microstrucute And Nanoindentation Characterization Of Micromechanics For Cementitious Materials

Concrete is a typical multiphase material,which is widely used in construction industry.However,the understanding on the structure and performance of the main hydrated products,such as calcium silicate hydrate(C-S-H),is not clear in many details.Micro-property of cementitious material was investigated in this paper by the means of X-ray diffusion method(XRD),X Ray Fluorescence(XRF),Mercury Intrusion Porosimerty(MIP),Scanning Electron Microscope(SEM)and nanoIndentation,to try to know more about the microscopic behavior from different scales.Taking the effect of cement grade,water/cement ratio,additional mineral and curing age into account,mineral content,porosity and micromechanical properties of typical cementitious materials were discussed qualitatively and quantitatively.In the micro-morphology experiment,the influence of material and preparing parameter on mineral content and porosity was analyzed by image processing technique.Based on pore structure tests with MIP method,the widely accepted Raleigh-Ritz(R-R)function was challenged and the lognormal distribution is found to be best to approximate the pore size distribution for cementitious materials.In the nanoindentation experiments,different phase of main hydrated products was separated by grid indentation and deconvolution analysis,obtaining the elastic modulus and hardness of each phase.This study on micro-structure and property of cementitious material leads to a better understanding on the relationship between micro-structure and macro performance,which is of great significance for improving the durability of cementitious materials and some special functions.