Title:
Modeling the Thermal Stresses at Early Ages in a Concrete Monolith
Author(s):
Eric Ayotte, Bruno Massicotte, Jules Houde, and Vladimir Gocevski
Publication:
Materials Journal
Volume:
94
Issue:
6
Appears on pages(s):
577-587
Keywords:
dams; freeze thaw durability; heat of hydration; mass concrete;
modeling; strains; stresses;
DOI:
10.14359/342
Date:
11/1/1997
Abstract:
This paper presents details of an experimental and numerical study of thermal strains and induced stresses in large-scale mass concrete. Three large-scale monoliths were built on a dam construction site in the James Bay Territory to monitor the thermal behavior of mass concrete subjected first to heat of hydration development and subsequent freeze and thaw cycles. The monoliths were instrumented with thermocouples and mechanical strain gages. The modeling of one monolith was carried out with the computer program ADINA. The modeling includes the development of a heat of hydration curve typical to the concrete used in dam construction. The mechanical properties of early-age concrete were based on measurements or evaluated from various references. It is shown that, due to an inadequate representation of the reference temperature, many nonlinear incremental commercial software systems cannot correctly simulate the stress history of maturing concrete with the temperature variation. The paper presents a modified step-by-step approach which improved the stress modeling within the available commercial software. Excellent agreement between measured and computed temperatures and stresses was obtained.