Code Provisions for High Strength Concrete Strength-Temperature Relationships at Elevated Temperatures.
Code Provisions for High Strength Concrete
Strength-Temperature Relationships at Elevated
Phan, L. T.; Carino, N. J.
Materials and Structures, Vol. 36, No. 256, 91-98,
codes; high strength concrete; concretes; temperature;
This paper presents results of experiments, conducted at
NIST and elsewhere, to measure compressive strength of
concrete at elevated temperature. The paper compares
the test data with existing design rules and
recommendations to assess their applicability to HSC.
Based on the compiled data, the paper proposes new
stength-temperature relationship for HSC and discusses
the need for standardizing the test procedure for
testing concrete at high temperature and for a revision
of the current design guides to include new data for
properties of concrete at high temperature. Degradation
of concrete strength due to short-term exposure to
elevated temperature has been studied as early as the
1950s. Among the early studies were those of Abrams
[1968, 1971], Malhotra , and Schneider [1983,
1985, 1988]. Results of these studies constituted the
technical basis for the provisions and recommendations
for determining concrete strength at elevated
temperature in many existing codes and authoritative
design guides. While these studies provided valuable
information on the variation of concrete strength as a
function of temperatures, almost all used specimens made
with NSC (according to the current ACI definition).
Thus, in light of the results of recent studies which
have shown that HSC behavior at elevated temperature may
be significantly different from that of NSC [Phan
(1996); Phan and Carino (1998, 2001)], question may be
raised as to whether existing design rules and
recommendations are applicable to HSC.