Effect of novel binaphthol admixture on the hydration characteristics and mechanical properties of OPC pastes

The main goal of the investigation reported in this paper was the preparation of a novel aromatic admixture and its use for improving the physicochemical and rheological properties of fresh and hardened ordinary Portland cement (OPC) pastes. The effects of the addition of 0·25, 0·50, 0·75 and 1·00% (by mass of OPC) of the novel aromatic organic admixture (sodium 5,5′-diformyl-2,2′-dioxido-1,1′-binaphthyl-4,4′-disulfonate (SDD)) on the hydration characteristics, rheological and mechanical properties of OPC pastes were studied. The admixture was characterised using elemental analysis, infrared spectra and hydrogen magnetic resonance spectra techniques. The results revealed that the addition of SDD to OPC pastes caused a notable improvement in both rheological and mechanical properties of various hardened cement pastes at almost all ages of hydration. The results of X-ray diffraction analysis, differential scanning calorimetry and thermogravimetric analysis obtained for the neat and admixed OPC hardened pastes indicated that the main hydration products formed were nearly amorphous and microcrystalline calcium silicate hydrates, gehlenite-like calcium alumino-silicate hydrate and/or calcium aluminate hydrate and portlandite.