Effect of polyurethane foam adhesive on the static mechanical properties of municipal solid waste incineration bottom ash (IBA)

• Published in: Construction & building materials 2022-03, Vol.325, p.126460, Article 126460
• Main Authors: Ma, Qiang, Chen, Jun-feng, Xiao, Heng-lin, Pan, Yu-tao, Song, Zhong-nan
• Format: Article
• Language: English
• Subjects: Municipal waste incineration bottom ash; Polyurethane foam adhesive; Scanning electron microscopy; Triaxial shear strength; Unconfined compressive strength
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2022.126460

•PFA can effectively improve the UCS of IBA rapidly, and the improvement effect increases with the increase of PFA content and PFA gelling time.•Shear strength, deformation resistance , total stress strength parameters and strain-softening behavior of IBA are greatly improved by adding PFA.•The internal structure of IBA is excellently enhanced by adding PFA, which ultimately results in the significant improvement effect of IBA at low confining pressure and minor axial strain.•The PFA is found by mainly wrapping around the surface of IBA particles or filling of the pores between the IBA particles by SEM.•This study will provide the way of a low and cost-effective magnitude of improved IBA, and the results serves as a reference for the recycling of IBA. Municipal waste incineration bottom ash (IBA) is a by-product of municipal waste incineration and is characterized by possessing non-cohesive and enriching in irregular particles. Associated with particles breakage, using such problematic materials as filler initiates the degradation of structure durability and mechanical properties in geotechnical engineering unless an appropriate improvement technique is adopted. In this study, the effect of Polyurethane Foam Adhesive (PFA) as a cementing agent was investigated on the mechanical behavior of IBA by a series of unconfined compressive strength and consolidated-undrained triaxial compression tests. The effect of PFA contents, PFA gelling time and confining pressures on the mechanical properties of IBA was also investigated. With the addition of PFA, the mechanical properties of IBA were significantly improved and the improvement effect increased with the dosage of PFA and the gelling time. It was observed that increasing PFA contents led to higher shear strength, deformation resistance and suppression of strain-softening performance. Furthermore, SEM (scanning electron microscopy) images showed that PFA wrapped around the surface of IBA particles and filled in the pores among the IBA particles. These demonstrate in the form of improving internal friction angle and cohesion of IBA, especially the cohesion which ultimately resulted in significantly improving in overall shear strength of PFA-improved IBA. This study offers an efficient way to improve IBA, and provides references for improving the recycling utilization rate of IBA.