Nano material has been regarded as a promising material with wide applications in cement-based materials because of its unique properties, such as small particle size, big specific surface area, and high chemical activity. Elastic modulus is one of the critical mechanics parameters of ultra-high performance concrete (UHPC). Currently, although the compressive strength of UHPC has been increased significantly, the increasing magnitude of elastic modulus of UHPC is far lower than that of compressive strength. To explore the feasibility of producing UHPC with high elastic modulus by nano alumina (NA), the initial mixture of UHPC was designed via MAA model, and the effects of different contents of NA on the fluidity, mechanical properties, and durability of UHPC were systematically studied. In addition, the influence of NA on the micro pore structure and micromechanical properties of UHPC was also investigated. It was found that, (i) the flexural strength, compressive strength, and elastic modulus of UHPC at curing age of 28 d were increased by 8. 23%—16. 31%, 8.04%—26.39%, 9.44%—16.55%, respectively, be-cause of the utilization of NA;(ii)the drying shrinkage and chloride-ion migration coefficient were reduced by 2.54%—13.01% and 8.21%—17.28%, respectively, due to the addition of NA;(iii)the pore structure of UHPC and the elastic modulus of UHPC paste could be improved via NA;(iv)the optimal content of NA was 1.0%, considering the effects of NA on the fluidity, mechanical properties, and durability of UHPC. The findings of this work are of guiding significance for the producing of UHPC with high elastic modulus. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.
