Non-linear moisture profiles and shrinkage in concrete members

Abstract

Synopsis A simple approach to the measurement of moisture variations in concrete prisms is used to produce profiles such as might occur in a waterproofed bridge deck slab. The method relies on segmentation of a number of companion blocks containing crack initiators. Shrinkage/weight loss curves are produced for small concrete cylinders with varied curing times. Cylinders cured for less than about four weeks show a bi-linear relation between shrinkage and weight loss, with little shrinkage due to early moisture loss and more rapid shrinkage with later losses. Combination of non-linear moisture profiles with the shrinkage/weight loss relations into a numerical analysis allows tentative estimates of axial shrinkage, curvature and self-equilibrating stresses in a cracked or uncracked reinforced concrete section with or without allowance for creep.