This article outlines an experimental and numerical study of the long-term interaction between silica fume and Portland cement in low-temperature-cured ceramics such as concrete subjected to air, water and sealed curing. For this purpose about 2000 kg of eight qualities of concrete were studied at 4 different ages, each over a period of 90 months. Half of the concretes contained 10% silica fume. Parallel studies of strength, heat of hydration, hydration and internal relative humidity were carried out. New and original results and analyses of the interaction between Portland cement and silica fume related to compressive strength, split tensile strength, hydration and internal relative humidity are presented. The project was carried out between 1989 and 1996.