Experimental studies of concrete relaxation in various modes

Abstract

Introduction. At present, creep is the main parameter determined in the long-term loading tests of concrete samples. However, creep appears to be only one of the deformation properties of a concrete sample during operation under the action of long-term loading. Another important property involves stress relaxation. Moreover, in individual problems (temperature problems, force redistribution problems, etc.), stress relaxation plays a more important role than creep. The introduction of a new test procedure can improve the accuracy of the obtained results (in standard creep tests, concrete relaxation is determined only mathematically), which in turn will increase the accuracy of calculations.Aim. To develop a procedure for testing concrete samples with the determination of their stress relaxation.Materials and methods. The article describes a methodology for conducting an experiment to study the relaxation of concrete samples in compression and bending modes, as well as the parameters of test benches, samples and the principles of load transfer.Results. The main results of experimental studies are presented graphically. An analysis of the results obtained was carried out; the convenience of conducting tests was evaluated.Conclusion. The prospects of the proposed approach for testing concrete samples are demonstrated, and recommendations for amending GOST 24544 are prepared.