Hydration, Pore Structure, and Strength Development of Belite-rich Cement with Phosphorous Slag Powder

Abstract

The study has investigated the hydration behavior and microstructure of bilite-rich cement (BC) containing 30% of phosphorous slag powder (PS) with age from the measurements of hydration products, pore structure, hydration heat, and strength development. Comparisons are also made with control bilite-rich cement. Tests carried out on specimens cured at different ages were: X-ray diffraction (XRD) analysis, differential scanning calorimetry-Cthermogravimetry (DSC-TG) analysis, mercury intrusion porosimetry (MIP) tests, hydration heat, and flexural and compressive strength, etc. Results show that PS could decrease the amount of CH, fill the capillary pores, decrease the hydration heat and delay the time of reaching the maximum exothermic rate, thus making the mortar more compact and durable. And after 28 days, PS resulted in a higher rate of strength development for the BC+PS mortar than that of BC mortar. Both flexural and compressive strength of mortar containing 30% of PS were comparable than the control mortar (without PS) at 180 days.