Use of bench-top NMR to measure the density, composition and desorption isotherm of C-S-H in cement paste

► The density of C-S-H, the binding phase of cement is measured using NMR and XRD for the first time. ► The density is ρ=2.68g/cm3 for an underwater cured, never dried, paste. ► The measured Ca/(Si + Al) ratio and the molar water content are: 1.53 and 1.92 respectively. ► A pore size resolved desorption isotherm is presented for the first time.