The benefic effect of Moroccan oil shale’s ash on blended cement (CMII)

Abstract

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.

Modelling and Optimization for Mortar Compressive Strength Incorporating Heat-Treated Fly Oil Shale Ash as an Effective Supplementary Cementitious Material Using Response Surface Methodology

“…The remaining 36 mixes were prepared by including the untreated (raw) and treated FOSA at three replacement levels, i.e., 10%, 20%, and 30%. These amounts and ratios developed the greatest results in the previous researches [ 42 , 48 , 49 , 62 ]. All ingredients were mixed as required according to the ASTM C305 procedures [ 63 ].…”

“…Several studies have investigated the use of FOSA-based mortar at natural sand to binder ratio of 3:1, water to binder ratio of 0.3–0.5, and FOSA replacement levels of 7–30%. The produced mortars provided a 28 day compressive strength in the range of 34 to 45 MPa [ 48 , 49 ]. The obtained high strength value was attributed to the development of hydration products, especially C-S-H.…”

“…On the other hand, most of the conducted research investigated the use of FOSA in its raw state without applying any considerable treatment. The FOSA raw material is usually burned at a temperature of 500–1000 °C, but no information on the burning time and exact temperature is provided [ 48 , 49 , 57 , 58 , 59 ]. Yet, the burning temperature profile should be controlled to ensure the best pozzolanic behavior [ 40 ].…”