GUO Q M, CHEN F, ZHANG Y C, et al． Road performance of fly ash-slag geopolymer stabilized feldspar powder［J］. Journal of Henan Polytechnic University( Natural Science)， doi: 10.16186/j.cnki.1673-9787.2024120060.

doi: 10.16186/j.cnki.1673-9787.2024120060.

Received： 2024-12-25

Revised： 2025-04-24

Online： 2025-06-12

Road performance of fly ash-slag geopolymer stabilized feldspar powder (Online)

Guo Qiaoming¹, Chen Feng¹, Zhang Yucheng², Yang Lu¹, Chen Hui¹, Zhao Hua², Guan Bowen³

1. Jiang Xi Communications Investment Group Co. Ltd, Nanchang，330199,China;2.School of Infrastructure Engineering, Nanchang University, Nanchang，330031,China;3.School of material science and engineering, Chang’an University, Xi’an，710064,China

Abstract：Objectives To explore the feasibility of large-scale utilization of feldspar powder in highway engineering and promote green development in the field of road construction. Methods Fly ash and ground granulated blast-furnace slag (GGBS), two types of industrial solid waste, were used as raw materials to prepare geopolymer cementitious materials. By varying the modulus of water glass and the Na₂O mass fraction, the Si/Al and Na/Al ratios of the geopolymer were adjusted. The relationship between these factors and the strength of the geopolymer was analyzed to determine the optimal geopolymer mix proportion. Feldspar powder was stabilized using the binary geopolymer composed of fly ash and GGBS. The road performance of the stabilized material was comprehensively evaluated based on unconfined compressive strength, shear strength, resilient modulus, expansion rate, shrinkage rate, immersion mass loss rate, and softening coefficient. Additionally, the microstructure of the stabilized feldspar powder was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) to investigate the stabilization mechanism of the geopolymer. Results The results showed that the strength and water stability of the stabilized materials were significantly enhanced by the geopolymer. Deformation caused by water absorption expansion and drying shrinkage was reduced. When soil was incorporated, the strength was increased, but water stability was decreased. Deformation caused by water absorption expansion and drying shrinkage was both increased. When the geopolymer content was 20% and the feldspar powder content was 80%, the 28 day unconfined compressive strength of the stabilized material reached 2.36 MPa. The resilient modulus was measured at 98.03 MPa. The expansion rate was 0.029%, and the shrinkage rate was 0.215%. The immersion mass loss rate was less than 2%, and the softening coefficient was 0.81. These properties met the requirements for high-grade highway subgrades, as well as light-traffic sub-base layers in secondary highways and light-traffic sub-base layers in high-grade highways. A large amount of amorphous gel was generated after the hydration of the fly ash-GGBS based geopolymer. Small amounts of Ca(OH)₂, CaCO₃, and feldspar crystalline phases were also detected. These products formed effective bonding between the particles of the stabilized material and filled the pores. The compactness of the material was enhanced, resulting in excellent road performance. Conclusions The findings of this study provided theoretical and experimental evidence for the engineering application of geopolymer-stabilized feldspar powder.

Key words: geopolymer; feldspar powder; highway engineering; road performance; curing mechanism