Title:
Enhancing Factors of Stone Powder for Hardened Mortar
Author(s):
Hongbo Zhu, Yilu Zhang, Hongxiang Gou, Liang Ren, and Qing Chen
Publication:
Materials Journal
Volume:
120
Issue:
6
Appears on pages(s):
121-128
Keywords:
hydrothermal synthesis; microstructure; stone powder; tobermorite
DOI:
10.14359/51739151
Date:
12/1/2023
Abstract:
To improve the added application value of an industrial waste stone
powder (SP), the optimizing mechanism of SP for the structure and
composition of hydrothermal synthetic hardened cement stone was
investigated in this paper. Cement was partially replaced by SP,
silica fume (SF), or ground-granulated blast-furnace slag (GGBS),
and then the microstructure with different SP content was tested
through X-ray diffraction, thermogravimetric analysis (TG-DTG),
mercury intrusion porosimetry (MIP), and scanning electronic
microscopy. The findings indicate that the incorporation of SP in
autoclaved products significantly enhanced compressive and flexural
strengths. As the proportion of SP in cement was increased, a
corresponding increase in the content of tobermorite within autoclaved cement mortar was observed. This increase in tobermorite concentration results in an initial rise followed by a subsequent decline in both compressive and flexural strengths. The maximum compressive and flexural strengths were achieved at an SP content of 15%. In addition, the mechanical strength was further improved by adding SP+GGBS or SP+SF. The strengthening mechanism of SP reveals that the change in the ratio of calcium and silicon ions (C/S) caused by SP in the sample was conducive to the formation of tobermorite and strength increase. Meanwhile, an increase in the quantity and a decrease in the crystal size of tobermorite were observed with an increase in the content of stone powder, resulting in a more compact microstructure of the sample. Moreover, the mechanical strength of cement composites doping SP+GGBS or SP+SF was further improved through superposition effects of SP and GGBS or SF with high activity. Currently, it is mainly applied to pipe pile products, and the strengthening effect of SP increases its use value. Meanwhile, the study of SP strengthening mechanism has laid a theoretical foundation for its application in high-strength autoclave and improved the relevant theory.