Effect of ambient temperature on the properties and action mechanism of silt-based foamed concrete

Abstract Foamed concrete involves pouring layers at different ambient temperatures. However, the mechanical indexes in the specification are obtained under standard curing conditions. This paper addresses the respective influences of different ambient temperatures on the mechanical strength of silt-based foamed concrete. Next, comprehensive experiments exploring the mechanism of effect of temperature on silt-based foamed concrete, including compressive strength, flexural-tensile strength, splitting strength and elastic modulus, California bearing ratio (CBR), scanning electron microscope (SEM), and X-ray diffraction (XRD), were conducted. The test results show that the compressive strength of silt-based foamed concrete distributed in the shape of a saddle with increasing ambient temperature. The optimal strength was obtained at approximately 20 ℃. Below 0 ℃, the hydration ceased to influence the structure significantly. The structure of the concrete could be repaired to some extent under the standard curing conditions. When the ambient temperature rose to 20 ℃, the mechanical strength of the concrete rose almost lineally. From 15 to 35 ℃, the change in mechanical strength was not apparent. When the temperature exceeded 35 ℃, the mechanical strength dropped significantly with the rise of temperature influenced by the evaporation. Although the mechanical strength could be improved to some extent with the progression of age after the temperature returned to 20 ℃, the strength was lower than the standard strength, especially in frozen state and high temperature state.