Title: On-Site Early-Age Monitoring of High-Performance Concrete Columns

Author(s): Buquan Miao, Omar, Chaallal, Daniel Perraton, and Pierre-Claude Aitcin

Publication: Materials Journal

Volume: 90

Issue: 5

Appears on pages(s): 415-420

Keywords: columns (supports); field tests; reinforcing steels; strains; temperature; thermal expansion; thermal stress; Materials Research

DOI: 10.14359/3869

Date: 9/1/1993

Abstract:
The results of on-site temperature and strain monitoring of columns made with high-performance concrete at an early age are reported. Two pairs of circular 850-mm-diameter reinforced concrete columns made of 80-MPa concrete were instrumented with the aid of vibrating wire extensometers. One of these columns was active since it was part of the structure of the new library of Concordia University in Montreal. The other was never loaded and was used as a mock column. The strains in the concrete and in the embedded steel, along with the internal temperatures and the ambient temperature and relative humidity, were recorded. The results of the experimental data show that the concrete is subjected to strains and stresses during the first 3 days due to thermal gradient and different thermal behavior of concrete and steel. It was found also that the coefficient of thermal expansion of early-age concrete is substantially higher than that of hardened concrete.