Enhanced Durability and Reactivity of a Portland Cement with Low Phosphogypsum Content

Minimizing the environmental impact and optimizing the performance of the cement manufactured is the magic formula sought to define the glorious trio of performance, cost, and environmental impact. The use of industrial by-products such as phosphogypsum can help to achieve the sustainability of the cement industry. An industrial cement series was used to investigate the effect of low phosphogypsum content on Portland cement reactivity with percentages ranging from 1 to 4%. The raw materials, clinker, gypsum, and phosphogypsum, were characterized by X-ray fluorescence, and the clinker mineralogy was determined by X-ray powder diffraction coupled with the Rietveld method analysis. The reactivity of cement was followed by isothermal calorimetry, compressive strength, conductivity measurement, and thermal analysis. The results revealed that there is an influence of phosphogypsum in this range of composition on the early cement reactivity. However, it may enhance the long-term cement reactivity and the concrete performance. It has been found that the isothermal microcalorimetry analysis method, is able to detect the formation of an exothermic component due to the precipitation of phosphorus in the form of apatite even at very low phosphogypsum integration rates.