| Abstrakt: |
This work aims to preserve high-quality of limestone ore, by using the low-grade limestone and to unveil the role of limestone composition in the formation of ye'elimite clinker with an emphasis on its hydration and resulting physical properties. To accomplish this study, two local limestones and one bauxite were selected and mixed together with 15 wt% of commercial gypsum. The resulted mixture was used to prepared a pallet pressed at 2 MPa. The obtained meals were calcined at around 1200 °C with soaking time of 1 h to produce clinker which is used to synthesize the CSA cement. The carracterisation of raw materials and product were carried out by using X-ray fluorescence (XRF), Fourier transform Infrared Spectroscopy (FTIR), Diffraction XRD, Isothermal Conduction Calorimetry (ICC), Scanning Electron Microscopy (S.E.M) as well as physico-mechanical testing on hardened specimens. The results show that both cements (CSA-1 and CSA-2) have high pH values (8.9 to 10.2, respectively). ICC results revealed that the reactions were strongly affected by gypsum content. Indeed, the XRD results showed that CSA-1 cement obtained with low-grade limestone presents a strong intensity of ye’elimite as the main crystalline phase as compared to CSA-2 cement obtained with high-grade limestone. Additionally, the compressive strength of the hydrated CSA-1 cement reached ~ 16 and 28 MPa after 1 and 28 days of curing, respectively as compared to CSA-2 cement (21.0 and 16.9 MPa). Hence, from the above results, local materials such as bauxite, low-grade limestone of Mintom, and commercial gypsum can be used to produce high-strength cement materials at early age which can be technologically applied in building and civil engineering applications. |
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