The Measurement of Shrinkage: Influence of Specimen Size

Abstract

The paper deals with the experimental determination of the development of shrinkage and mass losses during concrete maturation. Three types of concrete mixtures were prepared for the experiment. The shrinkage measurement was designed to measure the relative length changes along the central axis of the test specimens. The main aim of the experiments was the comparison of the shrinkage and mass loss values using specimens of different dimension. One set of each concrete contained specimens with the dimensions of 100×60×1000 mm. The other set contained specimens with the dimensions of 50×50×300 mm. The measurement of shrinkage and mass losses started approx. 1 hour after the fresh concrete was placed into the moulds. The relative length changes were recorded continuously using an inductive sensor during the first 48 hours of maturation. After the 48 hours, the specimens were demoulded and a long-term measurement was performed manually using a mechanical strain gauge. The outcome of the experiment is an analysis of the influence of specimen size on the resulting curve and values of shrinkage and mass losses.