Study on the multiscale properties of cement-based materials containing nano-bubble water

In this work, the effects of nanobubble water (NBW) on the durability, rheology, macromechanics, and microscopic properties of cement-based materials were investigated. NBW did not significantly improve the fluidity and compressive strength of the concrete with strength grades below C25; however, it did significantly improve the fluidity and inhibit the slump loss of concrete with strength grades above C30, while the compressive strengths of the samples at different ages increased to varying degrees. NBW could also improve the durability of the concrete (sulfate resistance, carbonation resistance, and single-side freeze-thaw resistance) to varying degrees. The hydration temperature test, XRD, TGA/DTG, and MIP results indicated that NBW promoted the hydration reaction process and the generation of hydration products such as CSH colloids and CH crystals, which could effectively improve the internal structure of the cement paste, thereby further affecting the macroscopic properties. The mechanism of NBW was such that the high potential adsorption force on the surface of the fine bubbles increased the number of ion nucleation sites in the suspension, which was beneficial for increasing the effective hydration products of the cement in the early stage. © 2022 Elsevier Ltd