密度等级对泡沫混凝土孔结构及力学性能的影响

Effect of Density Grade on Pore Structure and Mechanical Properties of Foamed Concrete

摘要: 泡沫混凝土的性能受其湿密度等级影响较大，此文利用扫描电子显微镜和图像分析软件Image Pro Plus分析了不同湿密度等级泡沫混凝土内部孔结构特征，研究了密度等级对泡沫混凝土力学性能和路用性能加州承载比(CBR)的影响规律。研究结果表明：泡沫混凝土内部气孔分布均匀，且基本为独立不连通的球形孔，随着湿密度增大，气孔的面密度减小，并且减少规律基本符合线性关系；泡沫混凝土无侧限抗压强度、劈裂抗拉强度和弹性模量均随着湿密度增加而增大；四种不同湿密度的混凝土7 d CBR值均高于100%，具有很强的抵抗局部变形能力。泡沫混凝土的抗压强度与其劈裂抗拉强度、弹性模量和CBR值具有良好的线性相关性。

Abstract: The performance of foamed concrete is greatly affected by its wet density grade. In this paper, the pore structure characteristics of foamed concrete with different wet density grades are analyzed by means of scanning electron microscope and image analysis software Image Pro Plus. The influence of density grade on the mechanical properties and California bearing ratio of foamed concrete is studied. The results show that the distribution of pores in the foamed concrete is uniform, and most of them are independent and disconnected spherical pores. With the increase of wet density, the surface density of the pores decreases, and the reduction law basically conforms to the linear relationship. The unconfined compressive strength, splitting tensile strength and elastic modulus of the foamed concrete increase with the increase of wet density. The CBR values of the foamed concrete with different wet densities are all higher than 100% at the age of 7 days, which means strong resistance to deformation. The compressive strength of foamed concrete has a good linear correlation with its splitting tensile strength, elastic modulus and CBR value.