Thermal Expansion Coefficient of Carbon Nanotubes Reinforced Face Slab Concrete of Rockfill Dam at Early Age

Abstract

Abstract: Thermal stress is the main cause of non-structural cracking of rockfill dam face slab concrete. The coefficient of thermal expansion (CTE) is directly related to the thermal deformation and thermal stress of concrete. Carbon nanotubes (CNTs) have good mechanical properties and unique nano-effects of one-dimensional nanomaterials. CNTs also have great potential in improving the CTE of face slab concrete. The construction mix concrete (JC) and the face slab concrete (NC) with 0.1% (mass fraction) CNTs were prepared, and the temperature stress testing machine (TSTM) was used to measure the free strain of the early age concrete under temperature matching curing (TMC) mode and the constant temperature mode. The CTE value of early age concrete was calculated and a time-varying CTE model of face slab concrete was proposed. The results show that the CTE of two kinds of face slab concretes quickly decrease to a minimum value after final setting, and finally slowly increase to a stable value. The incorporation of CNTs increases the CTE of the face slab concrete near the final setting, but reduces the stable value of the concrete CTE.

Key words: face slab concrete, carbon nanotube, thermal expansion coefficient, temperature stress test, early age, CTE model

CLC Number:

TU528

ZHAO Zhifang, WU Xu, ZHANG Zhenyu, QI Jieyi, ZHANG Guangbo, XU Jiaming. Thermal Expansion Coefficient of Carbon Nanotubes Reinforced Face Slab Concrete of Rockfill Dam at Early Age[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(2): 465-472.

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