Early-age thermal cracking performance of carbon nanotube modified face slab concrete

Abstract

The thermal cracking of face slab concrete (FSC) seriously affects the durability of face rockfill dams. The mechanical properties of carbon nanotubes such as high strength, excellent thermal conductivity provide great potential to improve the temperature cracking of the FSC. In this paper, the effects of CNTs on the thermal cracking resistance of the FSC at early ages were investigated in terms of mixture workability, pore structure, tensile modulus, and temperature stress testing machine test. It was demonstrated that the incorporation of 0.1 wt% CNTs significantly improved the pore structure of FSC and increased the tensile modulus of FSC at early ages. Besides, a model for the coefficient of thermal expansion (CTE) of FSC at early ages was established based on the temperature stress testing machine test, and the cracking comprehensive index, the cracking core index, and the cracking refinement index were compared. The incorporation of CNTs effectively reduced the CTE and the cracking temperature of FSC at early ages, and improved the ability of FSC to resist cracking in harsh environments. Therefore, CNTs exhibited a great potential to enhance the early-age cracking resistance performance of FSC.