Test and simulation of concrete surface factor under different wind speeds

Abstract Using the designed test device, the water loss and surface humidity of three strength grades of concrete with curing time under the condition of environmental wind speed of 0, 5, 10 and 15 m/s were quantitatively measured, and the surface factor test values of each strength grade of concrete under different wind speed conditions were further obtained. Based on the surface diffusion theory, the theoretical calculation model of concrete surface factor considering the influence of different wind speeds was proposed, and the experimental values were compared with the theoretical calculation values. The experimental and theoretical results show that: The surface factor of concrete can be divided into two stages: humidity saturation stage and humidity decline stage according to the humidity state of drying surface. For a specific concrete component, the surface factor in humidity saturation stage is only affected by the environmental wind speed, while the surface factor in humidity decline stage is affected by not only the environmental wind speed, but also the concrete strength grade. Within a certain range (Va ≤ 10 m/s), the surface factor of concrete in two stages increases significantly with the increase of environmental wind speed. When the wind speed exceeds this range, the effect of wind speed on the surface factor is small. When the environmental conditions are the same, the higher the concrete strength grade is, the smaller the surface factor is, on the contrary, the lower the concrete strength grade is, the larger the surface factor is in the humidity decline stage. The proposed two-stage calculation model of surface factor considering the influence of wind speed can better reflect the influence of environmental wind speed and concrete strength grade on the surface factor, and can be used to calculate the surface factor of concrete with different strength grade under different wind speed conditions.