title: The influence of superplasticizers on the first steps of tricalcium silicate hydration studied by NMR techniques.
abstract: The influence of superplasticizer sulfonated naphthalene formaldehyde (SNF) on the hydration process of tricalcium silicate (C3S) paste was investigated by (1)H nuclear magnetic resonance spin-spin and spin lattice relaxation times. The addition of SNF superplasticizer to C3S paste clearly affects the morphology and growth rates of the hydration products, mainly by increasing the dormant period length, which lasts for several hours more than in conventional C3S hydrated paste, while reducing the acceleration period length. The relaxation data indicated that a pronounced delay occurs in the C3S hardening when sulfonated polymers are added to the makeup water. For all the analyzed samples, prepared with a water-to-C3S ratio of 0.4, the decay of the echo magnetization has been fitted by adopting both a monoexponential and a biexponential relaxation model in order to evaluate the contributions from water in different regimes of hydration.
authors.affiliation: Physics Department and INFM CRS SOFT, La Sapienza University of Rome, P.le Aldo Moro 5, Rome 00851, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Pirazzoli
authors.forename: Marcella
authors.initials: M
authors.lastname: Alesiani
authors.forename: Silvia
authors.initials: S
authors.lastname: Capuani
authors.forename: Bruno
authors.initials: B
authors.lastname: Maraviglia
authors.forename: Rodorico
authors.initials: R
authors.lastname: Giorgi
authors.forename: Francesca
authors.initials: F
authors.lastname: Ridi
authors.forename: Piero
authors.initials: P
authors.lastname: Baglioni
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010968:Plasticizers; D016062:Porosity; D017640:Silicates / Q000737:chemistry*; D014867:Water
chemical_list: D017610:Calcium Compounds; D010968:Plasticizers; D017640:Silicates; D014867:Water; C031293:calcium silicate