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To realize high-efficiency CO2 absorption by fresh cement paste, ultrasonic vibration technology is introduced into the CO2 absorption test device used in this study. Influences of ultrasonic frequency on the CO2 absorption rate (CO2 AR) and the ultimate absorption amount of fresh cement paste are analyzed. Furthermore, the influencing laws of the CO2 absorption amount (CO2 AA) on the fluidity, pore distribution, and mechanical properties of cement paste under ultrasonic vibrating agitation are analyzed by measuring the variations of the CO2 AA of cement paste. Results demonstrate that ultrasonic vibrating agitation not only can increase the CO2 AR and ultimate absorption amount of fresh cement paste, but also can optimize the internal pore structure of materials and compressive strength of cement-based materials.

Apart from focusing on the analysis of the characteristics of reinforcing bars during corrosion, such as open circuit potential and polarization, the study also engages in the investigation of their corrosion in magnesium phosphate cement (MPC). For a more comprehensive understanding of the rusting performances, a comparison was made by an electrochemical workstation between the reinforcing bars in the MPC system and in the ordinary cement. Meanwhile, under an optical microscope, an observation was conducted on the corrosion morphology in MPC at different ages of concrete while during MPC hydration, an exploration based on pH changes and polarization curve theory was carried out to learn about the mechanism of the resistance of the reinforcing bars in MPC to corrosion. Despite their extremely slow rate, corrosion behaviors were practically found in the reinforcing bars in MPC. Both the changes in pH and the formation of ammonium phosphate metal complex in the weak base were considered in the study to be the control factors for the resistance of reinforcing bars in MPC to corrosion.

In order to improve the mechanical properties and brittleness of magnesium ammonium phosphate cement (MAPC), polypropylene fibers and EB fibers were added to the MAPC. The optimum fibers content was determined by evaluating the fluidity, flexural strength and compressive strength of the fibers-laden MAPC. The mechanisms of polypropylene fibers-based MPAC and EB fibers-based MAPC mortar samples were determined via micro-morphology analysis. The results show that the optimum polypropylene fibers and EB fibers contents range from 0.6%–0.9%, and that inclusion of both leads to an improvement in the strength of MAPC mortar. There exists a strong adhesive force between EB fibers and cement, which can prevent glass fibers from being pulled out of cement when it undergoes tensile stress. The polypropylene fibers, however, become eroded and weakened within the MAPC, which leads to a decline in adhesive force, and exposure of polypropylene fibers whenever the cement is subject to tensile stress.