ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 62, (4) 374 - 381 (2018)

Gu Chunping 1,2, Wang Qiannan 3, Liu Jintao 2,1, Sun Wei 3
1 College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310014, China
2 Key Laboratory of Civil Engineering Structures and Disaster Prevention and Mitigation Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310023, China
3 Jiangsu Key Laboratory of Construction Materials, School of Materials sciences and Engineering, Southeast University, Nanjing 211189, China

Keywords: Ultra-high performance concrete, Nano-TiO₂, Mechanical properties, Durability, Flexural load

In this study, the durability of nano-TiO₂ modified ultra-high performance concrete (UHPC) with and without a flexural load was experimentally investigated. Firstly, the mechanical properties of UHPC with various nano-TiO₂ contents were tested, and the results showed that UHPC with 1 wt% nano-TiO₂ exhibited the best mechanical properties. Then, 1wt% nano-TiO2 was added into UHPC to evaluate its effects on dry shrinkage, chloride ingress resistance, freeze-thaw resistance and carbonation resistance of UHPC. The effect of the flexural load on the durability of UHPC was also studied. The dry shrinkage of nano-TiO₂ modified UHPC was reduced compared with the control UHPC. The flexural load accelerated the chloride penetration process in the tensile region of the UHPC specimens, and the addition of nano-TiO₂ mitigated the negative influence of flexural load on the chloride ingress resistance of UHPC. Moreover, the addition of nano-TiO2 particles also improved the freeze-thaw resistance of the flexural loaded UHPC by reducing the mass loss under 800 freeze-thaw cycles. Carbonation was not detected in all UHPC specimens after being exposed to 60% CO₂ for 180 days. Furthermore, the MIP results indicated that the addition of nano-TiO₂ refined the pore structure of the UHPC, which improved the mechanical properties and durability of the UHPC.

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doi: 10.13168/cs.2018.0033
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