Effect of high temperature and accelerated aging in high density micro-concrete

Abstract

The design of concrete often requires numerous mix proportions and tentative mixings, which translates into a great number of specimens and tests. The process may be optimized by using small-scale specimens, which results in the saving of material, equipment and time, offering advantages such as better handling, easy kneading or smaller curing spaces. Nevertheless, the ability of small-scale specimens to reproduce the experimental properties determined through conventional samples is an open issue. The hypothesis of this study is that the differences between standard and small-scale specimens may be mitigated by applying a change of scale to the aggregates. The durability of high-density concrete for radiation shielding, in terms of weathering resistance and behaviour against heating cycles, has been determined by means of conventional and small-scale specimens (including scaled aggregates). The effects of various aggressive external agents (heating cycles, seawater and water with K2SO4) and the correlation between the results from scaled and standard specimens were determined. The analysis of the results enabled to establish the suitability of the use of micro-concretes to characterize concretes. In this study, the correlations between scaled and non-scaled models have been obtained in properties such as compressive strength, mass variation and ultrasonic pulse velocity after undergoing durability and thermal exposition tests.