A small-angle neutron scattering study of cement porosities

Several techniques for measuring the porosity and pore-size distribution in hardened cement paste (HCP) have given conflicting results. This is partly because these methods require drying or pre-treatment of specimens. Small-angle neutron scattering (SANS) allows investigation of the fine-pore porosity without any such pre-treatment. Measurements using the Pluto SANS spectrometer indicate a bimodal distribution of near-spherical pores with diameters of 5 and 12 nm. The former have a well peaked size distribution and account for 1-1.5% porosity. The pores are relatively unaffected by the water-to-cement ratios investigated although drying has the effect of collapsing the structure.