Formation of technological deformations in concrete structures and articles
The analysis of the influence of the geometric shape of concrete structures on the distribution of residual (technological, hereditary, initial) deformations was conducted. In the course of study the density and water absorption of individual sections of concrete beams with form factors Kf = 1 and Kf = 0.997 and dimensions 100ґ150ґ1200 mm were determined. In the beam with Kf = 0.997 the density changed at sections in the lower bound of the structure. The difference in the density of concrete of the same initial composition along the cross section of the concrete beam is 204 kg/m3 that led to a change of water absorption in the respective fragments of concrete. In areas with straight faces the water absorption was 5.56 % on average. This corresponds to water absorption of fragments of samples of the beam with Kf = 1.0. Fragments of samples on the faces with a modified form demonstrated the water absorption of 4.5%. This is lower than the water absorption of concrete in zones of faces without changing the shape by 20%. The analysis shows that the change in the density of the concrete of the same composition along the cross section of products with different shape factors is due to the development of technological deformations in the process of concrete hardening. By changing the geometric characteristics of the products it is possible to influence on the distribution of technological deformations, thereby causing a change in structural parameters of the initial composition of the concrete. This leads to the change in density of the concrete in the zones of concrete beams with different values of the form factor.