The research presented in this paper is about the mechanical properties of fiber-reinforced alkali-activated slag cementitious sandwich panels with different types and amounts of admixtures. The mechanical properties, drying shrinkage properties, and micro-morphology were used to determine the optimal ratio of the admixtures. The results show that the alkali-activated slag sandwich panels have the characteristics of light weight, high strength and excellent thermal insulation, and the factors such as magnesium oxide, expansion agent and solution temperature have significant influence on their mechanical properties and dry shrinkage. This paper provides a theoretical basis and experimental data for the preparation process and application of alkali-activated slag sandwich panels.

Alkali-activated-slag cementitious material (AASCM) is distinguished by minimal energy consumption, reduced pollution, and superior mechanical properties; however, it is prone to issues such as susceptibility to cracking and inadequate frost resistance. To facilitate its application in cold region construction, research on AASCM modifications was conducted following freeze-thaw cycle and chloride ion corrosion coupling tests. The test results show that the AASCM made of recycled rubber and coal ash does not change much in shape or appearance after 100 freeze-thaw cycles, with a mass loss rate of less than 5% and a compressive strength loss rate of less than 25%. Furthermore, the AASCM containing recycled rubber, coal ash, and straw fiber demonstrates an effective resistance to freeze-thaw and chloride ion coupling, maintaining its appearance and shape without notable changes and exhibiting a mass loss rate of less than 25% following 100 such tests. Following 100 tests for freeze-thaw and chloride ion coupling, the appearance and morphology of AASCM exhibited no significant alterations, with a mass loss rate below 5% and a compressive strength loss rate under 25%; microscopic analysis revealed that the C-A-S-H gel maintained a relatively dense and stable structure. Adding recycled rubber to the AASCM matrix can slow the spread of cracks, make the material more flexible, and make it more resistant to frost. Straw fibers can stop cracks from getting bigger, and adding coal ash helps make more C-A-S-H gel, which improves the AASCM’s mechanical properties.

Alkali-activated slag recycled cementitious material (ASRCM) has emerged as a sustainable construction material alternative due to its potential for industrial byproduct valorization and reduced carbon footprint. To study the effect of recycled material content on ASRCM performance, this paper systematically investigates the optimal dosages of recycled stone powder, recycled rubber, and flax fiber in ASRCM with a controlled variable method. The synergistic effects of the inclusion of recycled stone powder, recycled rubber, and flax fiber on macro-microstructural properties on the ASRCM have been analyzed. The results show that the incorporation of recycled materials can significantly enhance both the mechanical properties and workability of the composite, thereby improving the overall stability and performance characteristics of the material system. However, challenges remain in standardizing recycled material reactivity assessment and mitigating long-term durability concerns. More research is needed to investigate the service life and field-scale implementation of ASRCM to accelerate circular economy transitions of the construction sector in the future.