Improvement of the Hygrothermal Performance of Mud-coated Material Used in Traditional Bamboo-woven Mud Walls

ABSTRACT

As one type of ancient architectural walls, the bamboo-woven mud wall, with its use of regional materials and its simple structure, reflects the harmony of nature and the harmony between humans and nature. In this study, to enhance the comprehensive performance of bamboo-woven mud walls, four additives (i.e., white cement, medium gravel, diatomite and rice husk powder) were used to prepare mud-coated composite wall materials based on an orthogonal test. Using multiple nonlinear regression and the Gauss-Newton algorithm, the influence of the additive ratio was analysed, and the best ratio was determined. Then, an optimized mud-coated composite material was acquired. The results show that the additive ratio had a significant effect on the comprehensive hygrothermal performance of the mud-coated composite material. The additives showed the following descending order based on the sensitivities: diatomite, rice husk powder, white cement, and medium gravel. Additionally, the optimal ratio of $0.490\mathrm{\%}$ white cement, $8.333\mathrm{\%}$ medium gravel, $0.147\mathrm{\%}$ diatomite, and $12.5\mathrm{\%}$ rice husk powder, yielding better comprehensive hygrothermal performance compared to the traditional material. The optimized compressive property and the anti-erosion coefficient of the material increased by $16.95\mathrm{\%}$ and $97.75\mathrm{\%}$, respectively, compared with those of the original material, and the results met the corresponding requirements. With the optimized composition and microscopic morphology, the rice husk powder and diatomite chemically reacted with the cement in an alkaline environment, increasing the density of the interior structure.

KEYWORDS:

• Bamboo-woven mud wall
• hygrothermal performance
• microscopic analysis
• multiple nonlinear regression
• orthogonal test

Nomenclature

Table

Abbreviations

XRDX-Ray Diffraction

XRFX-Ray Fluorescence Spectroscopy

UCSUnconfined Compressive Strength

FTIRFourier Transform Infrared

SEMScanning Electron Microscopy

Acknowledgments

The authors would like to express appreciation for the financial support provided by the National Natural Science Foundation of Sichuan Province (2019YFS0488).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Science and Technology Department of Sichuan Province [2019YFS0488].