Durabilité des varietés de bétons

Abstract

The use of mineral admixtures and industrial wastes has marked the modern industry of concrete and cement. The major aim of this action is to meet the requirements of sustainable development and ecological issues. Certainly, the incorporation of those materials has a beneficial influence on the environment by the decreasing the rate of incoming clinker in the manufacture of concretes and cements. However, their qualities and engineering properties must be studied before proceeding to the practice adoption. In this study, we investigated the mechanical properties, hydration and durability of concretes and mortars based on limestone cement (CFC). The variables are the type of concrete/mortar (Ordinary O, Self-consolidating, and roller compacted R); the E/C report and the type of added mineral, limestone filler (CF) or silica fume (FS). Consequently, we have manufactured 16 concretes (O0.8, O0.5, O0.3F, O0.3S; A0.8F, A0.8S, A0.5F, A0.5S, A0.3F, A0.3S; R0.8F, R0.8S, R0.5F, R0.5S R0.3F and R0.3S), and 17 mortars (MO0,8, MO0,5ref, MO0,5 ,MO0,3F ,MO0,3S; MA0,8F ,MA0,8S ,MA0,5L ,MA0,5S ,MA0,3F, MA0,3S ,MR0,8F ,MR0,8S ,MR0,5L ,MR0,5S ,MR0,3F ,MR0,3S). The reference mortar MO0.5ref has been based on CEM I. The tests made on concrete are the compressive strength, the water capillary absorption, the mass change in the solutions of sulfate and sulfate/chloride, the penetration of chloride and SEM monographs. In addition to those tests, it has completed the study on mortar by the tests of heat of hydration by calorimetry, thermogravimetric analysis and rapid test of of chloride migration. The main results of this study are: the E/C report is the overriding factor for any type of concrete/mortar; the compacted mixtures have marked the lowest performance; the ordinary and self-consolidating mixtures have recorded similar values; silica fume has been beneficial especially for concretes under sulfate attack. Furthermore, it was concluded that: the influence of the porous structure of the mixtures is more significant than the chemical composition of the binder, especially in the case of the sulfatique attack; the capillary absorption is a good indicator of the durability, and can be correlated with the resistance to chloride than sulfates; the presence of chloride in alternation with sulfate has exacerbated the deterioration of concretes, and this effect was reversed in the case of mortars.