Title:
Quantifying Stress Development and Remaining Stress Capacity in Restrained, Internally Cured Mortars
Author(s):
J. L. Schlitter, D. P. Bentz, and W. J. Weiss
Publication:
Materials Journal
Volume:
110
Issue:
1
Appears on pages(s):
3-12
Keywords:
autogenous shrinkage; early age; internal curing; lightweight aggregate; mortar; residual stress; restrained shrinkage ring test; shrinkage; thermal cracking.
DOI:
10.14359/51684361
Date:
1/1/2013
Abstract:
Concrete can develop tensile stress when it is restrained from shrinking freely. Standard tests, such as the restrained ring test (ASTM C1581), can be used to quantify how likely it is that a mixture will crack due to the stresses developed under constant temperature conditions. The standardized restrained ring test is a passive test where the residual stress that develops due to restraint can be quantified using strains measured on the inner steel ring. The residual stress can then be compared with the concrete’s tensile strength to determine a mixture’s propensity for cracking. A new dual-ring test method has been developed to characterize the early-age behavior of mixtures that expand and/or undergo a temperature change. A new testing approach uses this dual-ring test to quantify the remaining stress capacity (that is, the additional stress that can be applied before the concrete develops a through crack). The new testing procedure allows stress to develop under constant temperature conditions before rapidly reducing the temperature to induce cracking. To demonstrate this approach, a plain and three internally cured mortar mixtures were tested and the results of these tests are discussed.