Effect of phosphorous slag on microstructure and hydration mechanism of cement-based materials

This paper reports on the studies of the microstructure and hydration properties of cement-based materials with added phosphorous slag by TG-DSC, SEM, XRD, and MIP. The results showed that the phosphorous slag and fly ash had almost equivalent hydration processes when the content was high. The ability of the phosphorous slag and fly ash to absorb Ca(OH)2 was about the same as the hydration process. However, at a later age, the hydration process of the phosphorous slag was faster than that of the fly ash. At an early age (7 d), threshold aperture, most probable aperture, and porosity decreased when the replacement ratio of phosphorous slag increased until 30% with no further increment afterwards. Meanwhile, the average pore diameter obviously increased even after 30% because the hydration product Ca(OH)2 in the cement particles that could excite secondary hydration was so few. © 2016 American Scientific Publishers All rights reserved.