Strength and Microstructural Analysis of Geopolymer Prepared with Recycled Geopolymer Powder

The strength and microstructural analysis of recycled geopolymer are presented in this paper. Five kinds of geopolymers containing 0%, 20%, 50%, 80% and 100 % of recycled geopolymer powder were prepared using metakaolin as the source material. The alkali activator solution was a mixture of sodium silicate (Na2SiO3) and 12 M sodium hydroxide (NaOH). The change laws of compressive and flexural strength of recycled geopolymer specimens were investigated. And the microscopic characteristics were carried out by SEM, XRD and FTIR to observe the internal morphology and analyze changes in components of recycled geopolymers at different substitution rates. The results show that, with the increase of substitution rate of recycled geopolymer powder, the mechanical properties of recycled geopolymers degenerate and the looser structure are formed. When the substitution rate is less than 50%, the recycled geopolymer specimen meets the use requirements of heavy traffic load class. And the specimen with 80% of substitution rate satisfies the requirements of plastering mortar.

Automated summary

The paper presents the strength and microstructural analysis of recycled geopolymer with different substitution rates. The mechanical properties of recycled geopolymers degrade with the increase of substitution rate, forming a looser structure. The study shows that recycled geopolymer specimens with a substitution rate less than 50% meet the requirements for heavy traffic load, while those with 80% substitution rate satisfy the requirements for plastering mortar.