Characterization and hydration of cements and pastes obtained from raw mix containing Moroccan oil shale and coal waste as a raw material

Abstract

In the present work, the hydration and physical properties of cements obtained from a raw mixes containing oil shale and coal waste as an alternative raw material were explored. A study of clinkers was carried out using chemical analysis and Rietveld analysis and the hydrated products were characterized by conduction calorimetry, X-ray diffraction, FTIR, Differential thermal analysis-thermal gravimetry and Scanning electron microscope. The findings showed that the cement paste containing both oil shale and coal waste had the highest compressive strength. According to the hydration studies, the four hydration steps were observed in all cements. The conduction calorimetry study showed the formation of the calcium monosulfoaluminate phase (AFm) in all cements which in cement containing coal waste was retarded by 50 h due to the high Na2O concentration in its clinker. Further, the identified hydration products: C-S-H gel, portlandite and Afm phase, which detected by XRD, FTIR and ATD/TG have been observed morphologically in SEM images. Moreover, the EDX microstructural study revealed that C-S-H gel contains a less amount of Aluminum and sulfur.This paper has been carried out as part of a CSIC-Mohammed V University of Rabat, cooperation programm (iCOOPA20067). Facilities given by IETcc (CSIC) and funding from BIA 2013-47876-C2-1-P and BIA BIA2013-43293-R projects as well as the Regional Government of Madrid Community and European Social Fund (Geomaterials Programme2 S2013/MIT-2914) are gratefully acknowledged.Peer reviewe