Abstract. We focused our research on recycling industrial wastes, fly ash (F.A), bottom ash (B.A) and oil shale ash (S.A) in cement production. The study concerns physico-chemical characterization of these products and the influence of their addition on the mechanical proprieties of the CPJ 45 cement. XRF allowed us to rank the three additives used according to their contents on major oxides. Coal ashes belong to the class F, and thus possess poozzolanic properties and oil shale ash belongs to the class C and possesses hydraulic and poozolanic properties. The crystalline phases constituting each ash were analysed by XRD. We observe in bottom ash the presence of quartz and mullite. The same crystals are found in fly ash with hematite and magnetite. Oil shale ash is composed of quartz, anhydrite, gehlenite, wollastonite and periclase. The microstructures of fly ash and bottom ash were studied using SEM. The bottom ash was composed respectively of fine particles that are generally irregularly shaped, their dimensions are between 5 and 28ȝm and of big particles(300 ȝm). The EDX analysis coupled with an electronic microscope provided some information about the major elements that constitute our samples. The dehydrations of anhydrous and three days hydrated cement were examined by DSC. For hydrated cements we noticed endothermic peaks related to the dehydration of CSH, CH and decomposition of carbonates. The study of the mechanical properties of CPJ 45 cement by adding different proportions of fly ash, bottom ash and oil shale ash helped clarifying the percentage of ash that leaded to improve the 28 days mechanical strength. The results show that the cements studied have their maximum mechanical resistance with the addition at 7% of fly ash or 10% of oil shale ash.

Abstract.Recycling of Tarfaya's oil shales (OSA) was conducted for two essential reasons: First, to follow the change of their mineralogical composition with the heat treatment and second to investigate the possibility of their use in building materials. The mineral compositions and the mineralogical transformations of the oil shale during their thermal treatment were followed respectively by X-ray fluorescence (XRF), by X-ray diffraction analysis (XRD) and Fourier transform infrared (FTIR). The XRF showed that the mineral composition of the ash burned at 850°C is similar to that of Portland clinker and the DRX showed the presence of quartz, mayenite, gehlenite, anydrite, hematite and lime as well as the existence of some characteristics phases of the clinker as C 2 S, C 3 A and C 4 AF. The Infrared spectrum showed the various functional groups that exist in OSA. The substitution of cement CMII by OSA increased the content of free lime and Blaine specific surface. The ash influenced beneficially the mechanical strength of the blended cement. The best results were obtained at all times of curing (2, 7, 28 and 91 Days) for the substitution of CMII by 7 and 10 % of OSA.

Recycling of Tarfaya’s oil shales (OSA) was conducted for two essential reasons: First, to follow the change of their mineralogical composition with the heat treatment and second to investigate the possibility of their use in building materials. The mineral compositions and the mineralogical transformations of the oil shale during their thermal treatment were followed respectively by X-ray fluorescence (XRF), by X-ray diffraction analysis (XRD) and Fourier transform infrared (FTIR). The XRF showed that the mineral composition of the ash burned at 850°C is similar to that of Portland clinker and the DRX showed the presence of quartz, mayenite, gehlenite, anydrite, hematite and lime as well as the existence of some characteristics phases of the clinker as C2S, C3A and C4AF. The Infrared spectrum showed the various functional groups that exist in OSA. The substitution of cement CMII by OSA increased the content of free lime and Blaine specific surface. The ash influenced beneficially the mechanical strength of the blended cement. The best results were obtained at all times of curing (2, 7, 28 and 91 Days) for the substitution of CMII by 7 and 10 % of OSA.