Mechanical and Physical Properties of Silt-Based Foamed Concrete with Different Silt Types

Silt-based foamed concrete, in which the cement is partially replaced with silt, has become a novel material in road construction projects. However, at present, only a small number of studies have been completed which have focused on different types of silt material and their influence. Therefore, to address these issues, this research investigation conducted experiments regarding silt-based foamed concretes to analyze their mechanical and physical properties. The compressive strength, flexural strength, elastic modulus, pore structure, dry shrinkage and water absorption were studied and analyzed in detail. Furthermore, the respective densities of foamed concrete, silt content and plastic index of silt were regarded as the influence factors. The results revealed that the compressive strength, flexural strength and elastic modulus of the samples increased with the increasing density, and decreased with the increasing silt content and plastic index. In most of the cases, the silt-based foamed concrete could satisfy the requirements as a subgrade filler, and the addition of silt was an effective measure by which to reduce the cost and pollution produced by cement. It was found that the increase of plastic index of silt will transform pore structures from uniformly dispersed closed pores into coalesced opening pores, in turn forming silt-based agglomerates. In addition, the increase in silt content and decrease in plastic index were observed to reduce the drying shrinkage. Furthermore, water absorption increased to average levels of 12% and 2.42%, respectively, as the silt content increased by 10% and the plastic index of silt increased from 7.2 to 15.4. The influence of silt on the properties of foamed concrete depended on the properties of silt and the effect of addition of the silt on pore structure of foamed concrete. The results of this study may provide an important reference to the application of silt-based foamed concrete in engineering projects.

Automated summary

This research investigates the mechanical and physical properties of silt-based foamed concretes. The results show that the compressive strength, flexural strength, and elastic modulus of the samples increase with density, but decrease with silt content and plastic index. The addition of silt can reduce the cost and pollution of cement. The study also finds that the pore structure, drying shrinkage, and water absorption are affected by silt content and plastic index.