Blast-Resistant Properties and Mechanism of Anti-Explosion Polyurea Coating

The mechanical strength, molecular structure and thermal properties of Qtech T26 anti-explosion polyurea (T26 polyurea) were studied by wide-angle X-ray diffraction (WXRD), differential scanning calorimetry (DSC), scanning electron microscope (SEM) and contact explosion experiment of polyurea coated reinforced concrete plate. The blast-resistant properties and protection mechanism of T26 polyurea coated reinforced concrete plate were investigated based on analyses of the macro morphology of reinforced concrete plate with or without coating and the micro morphology of coating. The results show that the tensile strength of T26 polyurea is 25.4 MPa and the elongation at break is 451.9%; the soft and hard segments of the molecular chain are arranged orderly, and the crystallinity of the microcrystalline region is 24.11%; the glass transition temperature of soft segment and hard segment was −44.9 ℃ and 36.5 ℃, respectively. After the explosion experiments, the uncoated reinforced concrete plate had a large pit on the contact blast face. The backburst surface appeared explosion earthquake collapse and fracture. The reinforced concrete plate with coating had a smaller pit on the contact blast face besides the softening of polyurea caused by the instantaneous high temperature. Moreover, the sparse tensile wave of the explosion reflection caused the damage of polyurea material, leading to the tearing of the coating material. As for the backburst surface coating, the polyurea coating weakened the effect of the explosion impact tensile wave, thus protecting the concrete material from breaking and preventing the explosion debris from splashing.