Development of a hydrophobic cement mortar with controllable strength: Preparation and micro-mechanism analysis

The widespread utilization of hydrophobic concrete in applications is often hindered by the significant decrease in mechanical properties observed when traditional modifiers are added to cement mortars. To address this issue, the present study introduces a novel hydrophobic additive called modified mica powder (MMAP). This additive has been developed specifically to enhance the water and corrosion resistances of cement mortar. To determine the optimal mix ratio, the effects of modifiers, particle sizes of MAP, and various preparation methods of MMAP were investigated. These parameters were analyzed in relation to the mechanical properties and water absorption characteristics of the MMAP modified cement mortar. As a result of the experiments, it was found that the capillary water absorption of the MMAP modified cement mortars was reduced by 23.5%-64.4% in comparison to that of the unmodified ones. More importantly, the MMAP had no adverse effect on the mechanical properties of the cement mortar, which was superior to that of the MAP addition using conventional methods. furthermore, the microscopic characteristics of both MMAP and MMAP modified cement mortar were examined using techniques such as FTIR, SEM, and EDS. Through these analyses, insights into the hydrophobic mechanism of the MMAP modified cement mortar were obtained, shedding light on the underlying processes and interactions responsible for its enhanced water resistance properties.