Influence of the w/c ratio on the hydration process of a magnesium phosphate cement and on its retardation by boric acid

3D microstructure of magnesium potassium phosphate ceramics from X-ray tomography: new insights into the reaction mechanisms

“…In fact, it is plausible that, in diluted systems, leaving the kinetic path, the reaction follows a different mechanism. The crystallization of metastable intermediate phases at high water contents (w/s ratios between 5 and 100) [16,[20][21][22] agrees with this view. For water contents in the range covered in the present experiment, after 30 min MKP was the only crystalline product detected [16,22], as confirmed by the obtained X-ray powder diffraction (Online Resource 2) and SEM results.…”

“…In this view should also be intended the use of a wide range of w/s ratio. As already showed, formulations with very different water contents may help to gain insights into the process leading to the development of properties in this class of ceramics [16,[19][20][21][22][23].…”

“…1; a lower content would leave a fraction of unreacted reagents and any excess should be segregated in pores within the volume. Studies on pastes and suspensions with large water contents have been frequently reported [16,[19][20][21][22], and Mg-P-based materials with excess of water have been considered for specific applications, like in the fabrication of injectable biomedical cements [23] (w/s up to 1). However, detailed characterization of the role of water in defining the microstructure in MPC is lacking.…”

“…In general, it is of practical importance to verify the role of water on the development of the coarse microstructure of MPCs (up to mm in pore size), because it may help to shed light on the reaction mechanisms, and, ultimately, help in product design. In fact, different reaction sequences have been reported in function of MPC formulation [16,20,22,26]. There is indication that this occurs in reason of the degree of supersaturation achieved in solution in the first stages of the reaction.…”

Prediction of Chloride Distribution for Offshore Concrete Based on Statistical Analysis

“…Interestingly, the curves for various w/c ratios in the same zone are almost parallel to each other. This suggests that the w/c ratio affects the magnitude of D more than the rate of change of D. This observation implies that the w/c ratio has a significant influence on the initial degree of hydration but little influence on the subsequent hydration rate [48].…”