Chapter 9-Volume Changes hooton2017.pdf

The age of concrete at loading the length of time

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The age of concrete at loading The length of time under load The volume of Aggregate, Va The thickness of the concrete element The relative humidity of the environment Volume Changes of Concrete Creep coefficient t e b d c c k k k k k Volume Changes of Concrete Partial creep factors kc= the relative humidity factor kd = a factor taking into account the age at which the concrete is loaded. kb = a factor taking into account the w/c and cement content of the concrete (same as for shrinkage) ke = a factor taking into account the effective thickness of the concrete element (Note: a different curve than for shrinkage) kt = a factor depending on the effective thickness and the time under load. Volume Changes of Concrete Calc. effective thickness, e m The first step is to draw a sketch of the element, including the dimensions, direction of interest for the shrinkage calculation, and the direction(s) of drying. Calculate the effective thickness on a unit volume (Vol.), perpendicular to the direction of shrinkage to be calculated, for a unit drying surface (S.A. exposed): (mm) exposed S.A. Vol. m e Volume Changes of Concrete CEB Creep, Kc
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