EXPERIMENTAL STUDY OF CREEP AND SHRINKAGE STRAINS IN FINE- AGGREGATE CONCRETES

Abstract

The paper studies creep and shrinkage processes running in fine-aggregate concretes with plasto-elastic properties (deformations) under short-time loading are different from those of standard heavy concretes. Experimental studies of creep and shrinkage strains in fine-aggregate concretes that are based on sands with different fineness moduluses permit to compare prestress losses resulting from the creep and shrinkage of concrete. Usually these factors produce an aggregate effect, which makes the study of the processes that run in concrete under long-time influence noticeably complicated. There paper contains analysis results obtained by experimental studies of concrete prisms at different initial strains in the range of , with loading age of t= 14 or 28 days and different properties of concrete mixes. Concrete mix properties were modified by using sands with different fineness modulus. Likewise in order to determine creep and shrinkage deformations due to long-time loads the samples were tested under stress during 14, 73 and 180 days. All experimental data have been systematized in tables and are represented by diagrams. The analysis has helped to investigate the effects of relative stains on the creep deformation in concrete and to define the boundary line between linear and non-linear creep with relation to the stresses in concrete. Analytical description of non-linear deformations was performed with the help of N.H.Arutyunyan’ and I.I.Ulitsky methods. The resultant calculations formed a basis for the recommendations to simplify problem solving methods considering non-linear creep of concrete.