Freeze-thaw damage evolution characteristics of foamed concrete based on three-dimensional laser scanning

In order to quantitatively evaluate the surface damage degree of foamed concrete under freeze-thaw environment and study its damage evolution characteristics, three-dimensional structured light scanning test, uniaxial compression test and relative dynamic elastic modulus test were carried out on foamed concrete with densities of 600 kg/cm³ and 800 kg/cm³. Geomagic Studio and Cloud Compare software were used to process three-dimensional point cloud data. Based on the parameters of slope root mean square Z₂, structural coefficient S_F, roughness profile coefficient R_p and three-dimensional roughness coefficient R_3p, the surface morphology and damage characteristics of foamed concrete under freeze-thaw environment were quantitatively analyzed. The results show that the surface damage of foamed concrete develops stage by stage, and the failure process shows the characteristics of spalling layer by layer and gradually developing from the middle to both sides. The surface morphology parameters of foam concrete are positively correlated with the number of freeze-thaw cycles. The damage rate of low-density foam concrete is faster. After 20 freeze-thaw cycles, the Z₂ value of 600 kg/cm³ specimen is 35.44 % larger than that of 600 kg/cm³ specimen. The grey correlation degree between the morphological parameters of 800 kg/cm³ foam concrete and the compressive strength is higher, which is above 0.62. There is a linear relationship between the Z₂ value and the compressive strength retention rate, and the correlation coefficient is above 0.91.