Residual Mechanical Properties and Explosive Spelling of Fibre-Toughened High-Performance Concrete Exposed to High Temperatures

摘要

In this paper, an experimental investigation was conducted to identify the relationship between residual mechanical properties and explosive spallingoccurrence of fibre-toughened high performance concrete exposed to high temperatures. The residual mechanical properties measured include compressive strength and tensile splitting strength, and fracture energy. A series of concretes were prepared employing OPC (ordinary Portland cement) and crushed carbonate. Steel fibre, polypropylene fibre, and hybrid fibres (polypropylene fibre and steel fibre) were added to enhance fracture energy of the concretes. After being subjected to high temperatures ranged from 200 ℃ to 800 ℃, the residual mechanical properties of fibre-toughened high performance concrete were investigated. For fibre concrete, although residual strength was decreased by exposure to high temperatures above 400 ℃, residual fracture energy was significantly higher than that before heating. Incorporating hybrid fibres seems to be a promising way to enhance resistance of concrete to explosive spalling.