Substitution of aluminous cement by calcium carbonates in presence of carboxylic acid

•HOAc has a remarkable dispersive effect over paste mixture M1.•The well-dispersed pastes lead to densification of the hardened material.•The mechanical properties of the densified materials are improved.•Materials based of mixtures: Secar 71+CaCO3+HOAc favor the formation of C4AC‾_H11. This paper presents results concerning the partial substitution of a calcium aluminate cement by calcium carbonate. The experimental parameters monitored in this study are the mechanical properties, the microstructure evolution through density measurements and the structure through analysis by X-ray diffraction. The major results of this study are the following: (1) It is possible to substitute a portion (10wt%) of an aluminous cement by calcium carbonate, while improving the mechanical properties of the hardened material. This is achieved with a mass percentage of the carboxylic acid between 1 and 5%, relative to the dry mass, which acts as a good dispersant and leads therefore to densification of the hardened material. (2) When the mix consists of 50wt% of aluminous cement and 50wt% of calcium carbonate, the mechanical properties of the cured material are low and this happens whatever the percentage of added dispersant is.