ASSESSMENT OF EXPERIMENTAL EVIDENCE FOR MODELS OF HYDRATED PORTLAND CEMENT

THE RELATIVE MERITS OF THE NEW AND OLD MODELS OF HYDRATED PORTLAND CEMENT ARE PRESENTED WITH AN ASSESSMENT OF PUBLISHED AND UNPUBLISHED EVIDENCE RELATING TO THE MODELS. THE CHIEF AREAS OF EVIDENCE DISCUSSED ARE THOSE PERTAINING TO SURFACE ENERGY OF CALCIUM-SILICATE-HYDRATE MATERIAL (C-S-H) BY HEAT OF SOLUTION, STOICHIOMETRY OF C-S-H, AND THE EFFECT OF INTERLAYER REHYDRATION OF D-DRIED C-S-H ON DENSITY MEASUREMENTS, C-AXIS AND HYDRATED RADII CALCULATIONS, LENGTH AND WEIGHT CHANGE ISOTHERMS, AND POROSITY AND MECHANICAL PROPERTY CORRELATIONS. A NEW TECHNIQUE OF MEASURING THE FLOW RATE OF HELIUM INTO INTERLAYER SPACES IS DISCUSSED IN TERMS OF EVIDENCE IT PRODUCES. IT IS CONCLUDED THAT THE NEW MODEL OF HYDRATED PORTLAND CEMENT MORE ACCURATELY ACCOUNTS FOR ITS NATURE AS INDICATED BY A WIDE VARIETY OF PROPERTIES. /AUTHOR/