Title:
Creep, Shrinkage, and Thermal Strains in Normal, Medium, and High-Strength Concretes during Hydration
Author(s):
Arshad A. Khan, William D. Cook, and Denis Mitchell
Publication:
Materials Journal
Volume:
94
Issue:
2
Appears on pages(s):
156-163
Keywords:
compressive strength; creep tests; curing; high-strength concretes; shrinkage
DOI:
10.14359/297
Date:
3/1/1997
Abstract:
This paper presents an experimental study on early-age shrinkage and thermal and creep strains of normal (30 MPa), medium (70 MPa), and high-strength (100 MPa) concretes subjected to sealed and air-dried curing. It was found that demolding at very early ages resulted in greater shrinkage and thermal strains in high-strength concrete than in medium strength concrete, which in turn showed greater strains than the normal strength concrete. It was also observed that creep of the high-strength concrete containing naphthalene-based superplasticizer is much more sensitive to the age of loading than the normal and medium strength concretes, with very early-age loading resulting in significantly higher creep. Predictions using the CEB-FIP creep expressions agree reasonably well with the measured creep strains, except for the case of high-strength concrete loaded at very early ages (i.e., less than 24 hr).