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Shrinkage – Compensated Concrete: A Review of Current Technology

• ID:

  1140

• ESCSI:

  4561.004

• Author:

  Klieger, Paul

• Publication Name:

  Presentation at 41st Annual Convention of NRMCA

• Type of Publication:

  Paper

• Publisher:

  National Ready Mixed Concrete Association (NRMCA)

• Dated:

  1971

• Issue/Volume:

  January 25

• Other ID:

• Page(s):

  3-18

• Reference List:

  N

• Abstract:

  Concrete is a material which shrinks slightly when exposed to a drying atmosphere, a situation prevailing in almost every use as a construction material. This small shrinkage, of the order of 0.05 percent, would be of little consequence except for two factors. First, there is almost always some restraint to this shortening. For example, a pavement slab is restrained by friction with the subbase, or a beam is restrained by the rigidity of the columns to which it may be tied. The second factor is the relatively low tensile strength of concrete. Restraint to drying shrinkage sets up tensile stresses, and when these exceed the tensile strength, cracking will develop.Mechanical prestressing is one means for avoiding the development of tensile cracks, whether the tensile stresses be load-induced or those developed by restrained shortening. The use of expansive cements, however, provides a means for achieving such prestressing by harnessing an internal expansion in the concrete with nothing more than the conventional amount of reinforcing steel. Of primary interest at this time is the use of expansive cements for shrinkage compensation, thus the name “shrinkage-compensating” cements.