Formulation et caractérisation de bétons bas pH

ABSTRACT Investigations were carried out to formulate and characterize low-alkalinity and low-heat cements which would be compatible with an underground waste repository environment. Pozzolans (high-silica product such as fly ash and silica fume) and blast furnace slag were added to Portland cement to decrease the cement pore solution pH to 11. The alkali content of the interstitial solution (≈ 1 to 5 mmol/L) of blend was strongly reduced which decreased the pH by more than one unity as compared with control samples. The blends exhibited a low heat output (temperature rise below 20°C). The prepared concrete specimens had a compressive strength higher than 70 MPa after one year of curing in 100% RH, a low shrinkage (−350 to −500μm/m) and it was possible to prepare workable concrete despite the very high amounts of pozzolans in the blends.