Development of ultra-light foamed insulation materials and interfacial bond behavior with fiber-reinforced alkali-activated composites

Abstract

Due to the complex construction process, short service life and serious environmental pollution, the traditional insulation engineering and formwork engineering have caused great challenges and obstacles to the realization of the " dual carbon " goal. This study developed a new green external insulation system that integrates insulation and formwork based on alkali activation technology. The preparation technology of ultra-light foam insulation material (ULFIM) and the interface design method between ULFIM and fiber reinforced alkali-activated composite material (FRAC) were proposed. The effects of rice husk ash (RHA) and polyethylene (PE) fiber content on the dry density, thermal conductivity, compressive strength, volumetric water absorption, and pore structure parameters of ULFIM were studied. The effects of groove width, groove depth, groove spacing, and groove density on the interfacial bond behavior of FRAC-ULFIM were discussed. The microstructure of ULFIM and the interface transition zone morphology of FRAC-ULFIM and FRAC-extruded polystyrene (XPS) were observed using scanning electron microscopy (SEM), and the mechanism of influencing factors on the corresponding indicators were revealed. The results showed that adding an appropriate amount of RHA and PE fiber had a significant positive effect on improving the performance of ULFIM. In the past, the optimal dry density and thermal conductivity of ULFIM were only 191.5 kg/m3 and 0.0494 W/(m·K), respectively, and the compressive strength at 7 d could be as high as 0.49 MPa. In addition, interface shear performance test results have shown that the "bridging effect" of PE fiber can effectively improve the shear strength and ductility of FRAC-ULFIM, which was 23.7% higher than the interface shear strength of FRAC-XPS under the same conditions. The groove treatment increased the interfacial shear strength of FRAC-ULFIM from 74.59 kPa to 266.37 kPa, with a maximum increase rate of 257.11%. The proposed new green external insulation system has significant potential application value.