Abstract:With increasing societal awareness of environmental protection, the production process of traditional cement has become an area in urgent need of innovation because of its significant carbon emission contributions and generation of industrial solid waste. As a new type of low-carbon cementitious material, geopolymers not only consume less energy and produce fewer carbon emissions but also effectively allow for the reutilization of industrial solid waste, demonstrating its immense potential for further development. However, the inherent brittleness and poor crack resistance of geopolymers limit their structural applications. The crack resistance of concrete can be significantly improved by utilizing self-stressing structures to generate internal stress or by taking prestressed concrete with its unique manufacturing methods. Furthermore, incorporating admixtures to enhance the material''s inherent crack resistance presents another viable strategy. Owing to their excellent mechanical properties, carbon nanotube fibers offer new possibilities for addressing these limitations of geopolymers. In this review, the use of carbon nanotubes (CNTs) to enhance geopolymer performance is investigated. A comprehensive analysis of existing studies reveals that the incorporation of CNTs significantly improves the crack resistance and mitigates the brittleness of geopolymers. Optimal overall performance is frequently reported at CNT dosages between 0.12 wt.% and 0.14 wt.%. These findings provide a theoretical foundation for the practical engineering of CNT-reinforced geopolymers and contribute to the development of sustainable construction materials.

Abstract:Nanhai Avenue, located in Nanchong, Sichuan, is a major urban road built along mountains. The project involves the comprehensive treatment of a high and steep slope, which is characterized by elevated height, complex geological conditions, and a large volume of landslide mass. Moreover, the newly constructed bridge structure that is present adjacent to the slope poses strict requirements for slope deformation control. Based on the high-slope project on Nanhai Avenue in Nanchong, in this paper, a finite element model is constructed using Plaxis software to study support measures for high slopes. The results reveal that in slope protection, anti-slide piles play a crucial role in bearing the majority of the landslide force, and after prestress is applied, frame anchor cables can significantly share the landslide force, reducing the displacement and internal force of anti-slide pile shafts. Frame anchor cables transfer the landslide force to deep anchored soil layers, significantly reducing the deformation of soil behind piles, which plays a key role in controlling deformation of the bridge adjacent to the slope and ensuring the safety of the bridge structure. It is anticipated that the results of this study will provide reference data for similar projects in the future.