Damage Evolution and Thermal Insulation Performance of Mullite Powder-Based Foam Concrete under Hot-Rain Cycling

DOI: https://doi.org/10.62517/jcte.202606404

Author(s)

Jingshuang Zhang1, 2, Haoyu Liang1, 2, *, Yanqing Wu1

Affiliation(s)

1School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan, Anhui, China 2Engineering Research Center of Underground Mine Construction, Ministry of Education, Anhui University of Science and Technology, Huainan, Anhui, China

Abstract

To solve the problem of cellular concrete tending to suffer damage under alternating conditions of high temperatures and precipitation, as well as undergoing a gradual deterioration of its performance in terms of thermal insulation, this study explored cellular concrete based on mulite powder. Two molding strategies were adopted – free foaming and restricted foaming – with different foaming agent dosages. Heat-rain cycle tests were performed to observe variations in indicators such as the rate of mass loss, the relative dynamic modulus of elasticity, the coefficient of thermal decay and the rate of temperature variation. The results showed that with the increase in heat-rain cycles, the rate of mass loss gradually increased, the relative dynamic modulus of elasticity continued to decrease, and the samples with higher doses of foaming agent exhibited more severe damage. After 80 cycles of heat-rain, the relative dynamic modulus of elasticity of the free foam and controlled foam samples, with a foaming agent dosage of 30%, decreased 42.0% and 27.3%, respectively, demonstrating that the controlled foam mitigates damage to the material. When the foaming agent dosage increases, the temperature attenuation coefficient first rises and then falls, and the constrained foamed specimen reaches a maximum value of 0.97 at a dosage of 20%. When the number of thermal-rain cycles increases from 20 to 80, the temperature attenuation coefficients between measuring points A and B, and between B and C, decrease by 12.9% and 31.6%, respectively, indicating that thermal-rain cycles weaken the temperature attenuation capacity of the material. These results can provide a reference for optimizing the mix proportion of mullite powder foam concrete and can also promote its application in building wall insulation systems.

Keywords

Foam Concrete; Hot-Rain Cycling; Damage Evolution; Thermal Insulation Performance

References

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