Properties of magnesium phosphate cement reinforced with natural brucite fiber

Abstract

Magnesium phosphate cement (MPC) is widely utilized owing to its excellent properties. However, MPC is a chemically bonded material; therefore, it has the disadvantage of being highly brittle. The introduction of fibers is a simple and effective way to improve its toughness. Therefore, this study was focused on the effects of brucite fiber (BF) on the working properties, mechanical properties, hydration products, and microstructure of MPC. X-ray diffraction, thermogravimetric (TG) analysis, mercury intrusion porosimetry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared (FTIR) spectroscopy were used to analyze the hydration products and microscopic morphology of the specimens. The results showed that the addition of BF reduced the fluidity of the MPC slurry, slightly prolonged the setting time, and reduced the hydration temperature. BF significantly enhanced the mechanical properties of MPC, particularly its flexural strength, which increased with an increase in BF content. The 7-d and 28-d strengths of the specimens with 20 % BF content increased by 72.5 % and 70.0 %, respectively, compared with the reference group. TG analysis showed that BF promoted the production of the hydration product K-struvite, and K-struvite production was almost saturated at 20 % BF doping. The SEM, EDS, and FTIR spectroscopy results showed that the MPC composite matrix containing BF had a denser structure. Moreover, bonding between the fibers and matrix was enhanced, owing to the involvement of BF in the hydration reaction. Additionally, the structure was more solid, which led to a significant decrease in brittleness and an improvement in other properties of the MPC.