Experimental study on mechanical properties of composite materials of concrete and foamed cement under uniaxial compression

To investigate the mechanical properties of concrete-foamed cement composite specimens (C-FCCS), uniaxial compression tests were conducted on composite specimens with varying proportions and strengths of foamed cement. The analysis focused on the peak compressive strength, peak strain, macroscopic failure morphology, and acoustic emission (AE) characteristics of C-FCCS. The experimental results indicate that the peak compressive strength of C-FCCS exhibits a negative correlation with the proportion of foamed cement and a positive correlation with the proportion of concrete. At foamed cement proportions of 10% and 20%, the peak compressive strength of C-FCCS is predominantly governed by concrete, with AE energy concentrated primarily during the initial loading phase and near the peak stress. In contrast, at foamed cement proportions ranging from 30 to 50%, the peak compressive strength is dominated by foamed cement, with AE energy concentrated around the peak stress. The peak strain of C-FCCS shows a trend of initially increasing and then decreasing with the increase in height ratio (Height ratio = Foamed cement height/C-FCCS height). Under different height ratios, the peak strain of C-FCCS is approximately 175.61-558.13% of that of pure concrete specimens. Furthermore, variations in the strength of foamed cement have a minimal impact on the peak compressive strength of C-FCCS but significantly affect the peak strain. The peak compressive strength of C-FCCS is about 77.67-83.87% of that of pure concrete specimens, while the peak strain ranges from 128.46 to 361.38%. Lastly, the macroscopic failure of C-FCCS is primarily characterized by tensile failure, with shear failure commonly observed at the edges and corner interfaces of C-FCCS.