Synergistic effect of PTB emulsion, CaCO3 whisker and Nano-SiO2 on the properties of cement-based materials

With the rapid development of the civil engineering industry, performance requirements for building materials are also increasing rapidly. It is particularly critical to improve the performance of cement-based materials using admixtures. In this study, the synergistic effect of PTB (COMPAKTUNA.PRO) emulsion, calcium carbonate whisker (CaCO3 whisker) and nano-silica (nano-SiO2) on material properties was analyzed. Macroscopic properties such as rheology, compressive strength, flexural strength, durability, bond strength, and permeable pressure were tested. Microstructures were analyzed using the porosity, hydration heat, X-ray diffraction, and scanning electron microscopy methods. The results revealed that the PTB emulsion, CaCO3 whiskers, and nano-SiO2 increased the plastic viscosity and yield stress of the cement. When the nano-SiO2 content was high, the fluidity of the slurry decreased significantly. Overall, PTB emulsion, CaCO3 whisker and nano-SiO2 can improve the strength, durability, bond strength, and permeability of composite materials. PTB emulsions can prolong the hydration process, resulting in low early strength and reduced compressive strength. However, they play a key role in terms of improving durability, bond strength, and permeability pressure. CaCO3 whiskers yield slight improvements in various properties. Nano-SiO2 can promote the hydration rate and hydration effect, thereby improving the strength, compactness, and properties of composite materials. Performance can be optimized by leveraging these synergistic effects and each material has its own unique advantages and limitations. In engineering applications, critical properties should be considered when selecting appropriate admixture contents. This study aimed to improve various properties and to develop materials that are suitable for the complex environment of underground engineering.