Behavior evaluation of hybrid fibre-reinforced reactive powder concrete after elevated temperatures. (1st November 2021)

• Record Type: Journal Article
• Authors: Mao, Zhenhao; Zhang, Jicheng; Luo, Zhuozhuo; Ma, Qiankun; Duan, Yanni; Li, Shijie; Miao, Yuan
• Is Part Of: Construction & building materials. Volume 306(2021)
• Publication Date: 2021-11-01
• Subjects: Reactive powder concrete -- PP fibres -- Steel fibres -- Elevated temperature -- Mechanical properties -- Microstructure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.124917
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Performance of RPC with different fibre dosages after high temperature is discussed. After 300 ℃, the strengths of all RPC begin to drop as temperatures rise. RPC showed increasing mass loss and water absorption when temperature increases. RPC with with 2% steel fibre and 0.15% PP fibre showed the best performance. Equations between the residual strengths and the temperatures are established. Abstract: This research was aimed to evaluate the performance of reactive powder concrete (RPC) mixed with steel fibre and polypropylene (PP) fibre after exposure to 20 ℃–800 ℃. The volume contents of steel fibre and PP fibre are (2%, 0%), (2%, 0.1%), (2%, 0.15%) and (2%, 0.2%), respectively. Residual mechanical properties of cubic compressive strength and split-tensile strength were measured. Besides, physical parameters such as mass loss and appearance change after different temperatures have also been determined. The thermal deterioration of RPC is assessed by water absorption and sorptivity. Results show that the residual strength increased from ordinary temperature to 300 ℃. However, it's decreased gradually as temperatures rise. RPC with 2% steel fibre and 0.15% PP fibre showed the best performance regarding spalling resistance and mechanical characteristics compared to the others. In addition, all specimens showed increasing in mass loss and water absorption with the increasing temperature. Based on the experimental results, equations to express the relationships of the strength with the heating temperatures are established. Distinct changes in the microstructure of RPC reveal mechanical properties from a macroperspective.