Briques silico-calcaires autoclavées: influence de l’addition de laitier de haut fourneau sur la formation des phases

The mechanical properties of sand-lime bricks produced by autoclaving under different conditions and incorporation of granulated slag have been investigated previously. In this study, the relationship is established between the structure, the phases formed and the strength. Based lime and granulated slag a new binder is developed. This is cured at saturated vapour pressures of 1.0 and 1.8 MPa. The results showed a decrease in compressive strength due to the substitution. The microstructure analysis showed that reaction products consist mainly of 11 Å tobermorite and xonotlite. Also, when increasing the autoclave temperature, it results in an increase in xonotlite relative to tobermorite. The X-ray diffractions of these phases are very low, hardly visible; they are masked by the presence of quartz. Their intensities increase with the presence of slag. The slag seems more reactive with lime than quartz. Observations with the scanning electron microscope allow better to appreciate these phases. By its composition to amorphous structure, the granulated slag does not release new distinct phases of hydrates.