Determination of scale and correction factors for fine-grained concrete samples
The paper presents the results of a determination of scale and correction factors for fine-grained concrete samples. The compression strength of the studied samples, their scale and correction coefficients, as well as mean square deviations and coefficients of variation, were determined according to GOST 10180-2012 “Concretes. Methods for Strength Determination using Reference Specimens”. The determined differences between the values of compression strength of fine-grained concrete samples at the natural moisture content are as follows: for samples with a working section area of 100 cm<sup>2</sup> and 50 cm<sup>2</sup>- 3.65%; for samples with a working section area of 100 cm<sup>2</sup> and 25 cm<sup>2</sup> - 21.17%. The differences between the values of compression strength of dried concrete samples are: for samples with a working section area of 100 cm<sup>2</sup> and 50 cm<sup>2</sup> - 21.18%; for samples with a working section area of 100 cm<sup>2</sup> and 25 cm<sup>2</sup> - 41.87%. Reducing the humidity of samples to zero leads to an increase in the compression strength of fine-grained concrete: for prisms with dimensions of 40×40×160 mm by 73.5%; for cubes with a rib size of 70.7 mm - by 73.2%, for cubes with a rib size of 100 mm - by 48.2%. It was experimentally established that for samples with dimensions of 70.7×70.7×70.7 mm and 40×40×160 mm; the scale factors are 0.85 and 0.73, respectively, as compared to the reference sample sized 150×150×150 mm. In compression strength tests of fine-grained concrete, the correction factor for samples dried to a constant weight is 0.64 as compared to samples with 10% humidity.