Abstract
This paper mainly studies the early autogenous shrinkage characteristics of Ultra-Fine Fly Ash (UFA) and the influence of UFA on the early cracking sensitivity of concrete. Use UFA equivalent weight to replace the cement preparation of UFA road concrete, apply self-designed self-shrink testing device for concrete test the autogenous shrinkage deformation of the concrete at the early age (within 72 hours), and using the plate- limited shrinkage cracking test study the surface cracking resistance of the concrete within 26 hours, on the basis of the test, evaluate the early cracking sensitivity of UFA road concrete. With the incorporation of UFA, the early autogenous shrinkage deformation of the concrete is significantly reduced, while maintaining the same flow conditions, it significantly lower than the reference concrete, early crack resistance is better than the reference concrete, and with the increase of UFA content, the early cracking resistance is enhanced. The incorporation of appropriate amount of UFA can effectively reduce the early autogenous shrinkage of road concrete, thus reducing the sensitivity of early cracking and prolonging the service life of pavement structure. It also provides the theoretical and technical support for the application of UFA in practical engineering.
