Abstract
The stability of conventional concrete mixture was investigated using an inclined plane method. The experiment consisted of two steps: first, the research was made to determine the influence of coarse aggregate content in aggregates mixture on the stability and sliding of concrete mixture, when the specimens of mixture are on the inclined plane without additional roughening of surface; second, the research was made to determine the influence of inclined plane surface roughening on the stability and sliding of concrete mixture. During the research the condition was checked: the concrete mixture on the sloping plane will be stable, if the yield stress τ0 is higher than the shear stress τ in. (τ 0 ≥ τ). The shear stresses and rheological property yield stresses of conventional concrete mixtures were calculated analytically by using an empirical formula. Test results showed that the increase of coarse aggregate (4/16 fraction gravel) content from about 417 to 1175 kg in concrete mixture is enough to achieve the stability of concrete mixture, when plane inclination angles are 25°, 35° and 45°, but not enough to stop sliding process. In this case, additional implements are needed to increase the adhesion of fresh concrete to the base. By using the inclined planes, which were coated with a special dimpled membrane and geotextile, the fresh concrete does not slide downwards by inclined plane.
Highlights
The aim of this study is to determine an effect of coarse aggregate content in the total aggregates mixture on the stability and sliding of fresh concrete, when the samples of fresh concrete are on the inclined plane without and with additional roughening of surface
When the angle of the plane inclination increases from 25 to 45°, the shear stress of concrete mixture varied in the range from 183.98 to 15.71 Pa, from 412.07 to 50.83 Pa and from 636.90 to 101.00 Pa
By using Microsoft Excel program was identified the best dependence between the sliding speed and shear stress values of fresh concrete samples according to the best empirical coefficients values of equations
Summary
Fresh concrete mixture is a heterogeneous suspension which consists of various constituents. Those various constituents distinguish in different shape, size, material properties and has an effect on workability of fresh concrete (Jiao et al 2017). Cement paste is one of the main constituent parts of concrete, which covers aggregates and fills gaps between them, and makes the flow of concrete mix easier. Koehler and Fowler (2004) confirmed that the increased volume of paste increases the flow factor and reduces yield stresses and plastic viscosity. It is estimated that in cement which contains high amount of C3A and alkaline, the reduction of gypsum to silica ratio reduced the yield stresses, but did not change the plastic viscosity
Published Version (Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have