CONCRETE IN HOT ENVIRONMENTS - CHAPTER 8 pot

Chapter 8

Creep

8.1. INTRODUCTION

Creep may be defined as the increase in deformation with time, excluding

shrinkage, under a sustained stress. Such a deformation occurs in metals at

elevated temperatures but in concrete it takes place at room temperatures as

well. Hence, the importance of the creep behaviour in daily practice.

In the following discussion a distinction is not always made between cement

paste and concrete. Creep behaviour of concrete is essentially similar to that

of the paste because the aggregate hardly exhibits any creep. Hence, in

discussing creep qualitatively, paste and concrete are interchangeable. On the

other hand, aggregate properties and concentration affect creep quantitatively,

and in this context there is a significant difference between creep of the cement

paste and that of concrete. This aspect, however, is dealt with later in the text

(see section 8.4.2.1).

Finally, creep is usually measured by the length changes involved and is

expressed quantitatively by the corresponding strains,
1/10, or by the

corresponding strains per unit stress. The latter is known as ‘specific creep’

(see section 8.4.2.2).

Copyright 1993 E & FN Spon