Enhancing Concrete Performance in Low Vacuum Environments: Strategies and Mechanisms

To enhance the service stability of concrete suffering from a low vacuum environment, the effects of silica fume (SF), redispersible latex powder (RDP), and polyethylene fibers (PEF) on concrete strength and permeability were investigated, and the potential mechanisms were analyzed. Results indicated that SF-enhanced concrete demonstrated a higher strength compared to reference concrete. However, the enhancements from SF may be diminished under prolonged low vacuum conditioning, potentially due to the more significant shrinkage induced by such environments. Although the addition of RDP reduced the compressive strength of concrete, it enhanced the flexural strength and reduced gas permeability. Particularly after low vacuum treatment, the flexural strength increased by 27.4% due to accelerated polymer film formation caused by rapid water loss. The addition of PEF enhanced both the compressive and flexural strength of concrete. However, after low vacuum treatment, a notable reduction in the toughness of PEF-reinforced concrete was observed, primarily attributed to the low vacuum environment diminishing the strain-hardening behaviors. The effectiveness of conventional methods for enhancing concrete performance would be altered in a low vacuum environment. Therefore, it is essential to consider these alterations when developing enhancement techniques for concrete under such conditions.