Study on the solid waste-EPS lightweight roadbed suitable for soft loess subgrade in the Yellow River area

Abstract

In response to the engineering difficulties of soil scarcity, loose structure of loess, and poor road performance in the construction process of roadbed engineering in the Yellow River Basin, this paper introduces micro powder materials recovered from the processing of basalt stone, combined with fly ash to regulate alkali activation activity to prepare cementitious materials, which can replace conventional Portland cement to improve the mechanical properties of loess in the Yellow River Basin. On the one hand, it can reduce the resource and energy consumption caused by cement production and respond positively to the national requirements for green, low-carbon and high-quality development; On the other hand, by adjusting the dosage of the above-mentioned silt improvement and solidification agent, the problems of poor gradation and poor cohesion of the silt can be improved, and its road performance can be enhanced to alleviate the pressure of soil extraction in engineering. Based on the above background, this article takes basalt powder and fly ash as the core raw materials, and cooperates with naphthyl water reducer, alkaline activator (sodium hydroxide, sodium silicate, and soil stabilizer). Orthogonal experimental design method is used to test the compressive strength and infrared spectrum, and other methods are used to study and compare the mechanical properties of alkali activated multi-source solid waste materials under different proportioning conditions. The research results indicate that increasing the dosage of sodium hydroxide can enhance the polymerization reaction of basalt fly ash geopolymer and improve the compressive strength of the curing agent; Orthogonal optimization has proven that the optimal mix ratio is achieved when 6 g of sodium silicate, 2.4 g of sodium hydroxide, and 13.2 g of soil stabilizer are added to the specimen, resulting in the highest compressive strength. Infrared spectroscopy testing revealed that alkali excited multi-source solid waste cementitious materials contain various characteristic chemical bonds and bound water, proving that the geopolymer reaction improves the overall strength of the material. This study can provide experimental basis and application reference for related engineering construction. The improved mechanical properties and densified microstructure of the stabilized loess indicate its potential application in highway embankment slopes and weak floodplain soil stabilization. The proposed solid-waste-based geopolymer system may contribute to slope hazard mitigation and long-term stability control in geotechnical engineering.