Title: Effect of Microstructure Variation on Damage Evolution of Concrete at High Temperatures

Author(s): Jingsi Huo, Bao Jin, Qi Yu, Yuanming He, and Yanzhi Liu

Publication: Materials Journal

Volume: 113

Issue: 5

Appears on pages(s): 547-558

Keywords: compressive strength; damage evolution; high temperature; mechanical behavior; microstructure; modulus of elasticity

DOI: 10.14359/51689102

Date: 9/1/2016

Abstract:
The mechanical behavior of concrete at elevated temperature up to 800°C (1472°F) was examined by means of experimental investigation, with emphasis on the effect of microstructure variation on damage evolution of concrete. First, a specially built electrical furnace was employed for the application of high temperature on the concrete specimens. Forty-two static compressive tests at elevated temperatures were then presented. The static stress-strain relationships of all the concrete cylinders were recorded and compared. Further discussion focuses on investigating the effect of the high temperature on the mechanical property of concrete with different aggregate and water-cement ratios (w/c). It was found that the high temperature resulted in lower concrete strength. Furthermore, a series of experimental techniques were employed to examine the development of concrete microstructure, including X-ray diffraction (XRD) investigation, scanning electron microscope (SEM) test, and mercury intrusion porosimetry (MIP) analysis. The series of test results revealed the strength deterioration mechanism of the concrete at elevated temperatures.