Cross-sectional strength gradients in high strength concrete columns

✍ Scribed by S.L. Mak; M.M. Attard; D.W.S. Ho; P.LeP. Darvall

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 937 KB
• Volume: 24
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(94)90095-7

✦ Synopsis

Vertical variations of strength in a structural element is a well-established phenomenon. In large cross-sections, horizontal strength gradients can also occur because of local differences in humidity and temperature conditions. When the heat of hydration of concrete is free to dissipate from a cross-section, the temperature variations within a cross-section imply not only differing rates of strength development but also a risk of thermal cracking due to high temperature gradients.

A series of columns of two cross-sectional dimensions were cast in the laboratory for concrete mixes with 28-day compressive strengths ranging from 40 to 115 MPa. Compressive strength results of vertically drilled cores showed the presence of significant cross-sectional strength gradients. Three-dimensional core strength distributions were constructed from which effective cross-sectional strengths of unreinforced in-situ concrete were calculated.