Open AccessStudy of Quality Parameters of Long-Term Strength of Cement Composites
Author(s) -
I. N. Maksimova,
Н И Макридин,
A V Dergunova,
D N Barabanov
Publication year - 2021
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/1079/6/062029
Subject(s) - materials science , acoustic emission , bending , composite material , deformation (meteorology) , cement , fracture (geology) , fracture mechanics , compression (physics) , reliability (semiconductor) , structural engineering , engineering , power (physics) , physics , quantum mechanics
The currently widespread assessment of concrete quality, including reliability, by traditional mechanical characteristics is ineffective, since these state parameters do not take into account changes in the strength and deformation properties of concrete under the influence of temporary processes of microcracking during loading when diagnosing structural materials. Modern development of fracture mechanics has made it possible to establish scientific principles for evaluating materials and testing methods and to propose together force, strain, energy and acoustic criteria for crack resistance that determine the actual limit States of their structure in terms of strength and deformability and thus allow predicting the performance of the material under load. This paper presents the results of experimental evaluation of mechanical failure criteria and regularities of changes in acoustic emission parameters from the loading intensity during non-equilibrium mechanical tests for three-point bending of experimental samples with an initial incision depth of 13 mm. Analysis of the influence of the concentration and the introduction of SP-3 on regularities of changes in the coefficients of increase of controlled criteria of crack resistance in time relative to 28-day age quite clearly suggests, first, that the change of parameters of criteria of crack resistance in time has a wavelike nature, and the change in strength under axial compression, and, secondly, about, that the modified structures of cement stone samples relative to the control composition generally give significantly better indicators not only of the growth coefficients of the compared quality criteria, but also of the absolute values of the criteria for crack resistance up to 18 years of age.