On the action of capillary pressure in fresh concrete

Abstract

Capillary pressure and plastic shrinkage have been measured simultaneously. The action of capillary pressure in fresh concrete is assumed to be the cause of plastic shrinkage. Characteristic results are presented to verify the essential statements of this hypothesis. The influence of water-cement ratio on plastic shrinkage is dealt with in more detail. It is shown that plastic shrinkage leads to highest contraction of fresh concrete in the range 0,5 ≤ W/C ≤ 0,6. Rewetting the dried surface stops immediately further contraction. The influence of additives on plastic shrinkage is mentioned and discussed on the basis of the presented results.