Title:
Assessment of Toughness of Concrete Subject to Elevated
Temperatures from Complete Load-Displacement Curve-Part
II: Experimental Investigations
Author(s):
Binsheng Zhang, Nenad Bicanic, Christopher J. Pearce, and Gojko Balabanic
Publication:
Materials Journal
Volume:
97
Issue:
5
Appears on pages(s):
556-566
Keywords:
curing; strength; toughness.
DOI:
10.14359/9881
Date:
9/1/2000
Abstract:
In Part I of this paper; six energy- and deformation-based toughness indexes were summarized and derived for assessing the concrete toughness based on a two-portion complete load-displacement relationship compromising parameters such as load, characteristic displacements, and geometric coefficients, by considering the effect of self-weight of the beam specimen under three-point bending. In this paper; the effects of heating temperature, exposure time, and curing age on the fracture and toughness of concrete were experimentally investigated by conducting three-point bending tests on a total of 55 notched plain concrete beams that had been preheated at tempera-tures between 100 and 600 C over varied exposure times up to 168 h and for four ages ranging from 7 to 90 days. The relationships of these parameters with heating scenarios and curing ages were established. Thus, six toughness indexes could be used to quantitatively assess the toughness of concrete in varied heating scenarios and curing ages. A higher heating temperature always led to a larger toughness. A longer exposure time also led to a larger toughness, but such an effect was more significant at the early exposure age under 12 h, and became weaker thereafter. A longer curing age only led to a lower toughness in the first 28 days and did not significantly affect concrete toughness after 90 days.