Experimental Research On Bonding Behavior Between XPS Insulation Board Layer And Structure Layer

As an important architecture energy efficiency technology, external thermal insulation system was highly valued worldwide. Because it had series of advantages such as reducing the thermal bridge and increasing the building clearance. Exterior insulation technology used in engineering generally operated according to engineering experience, which lacked the in-depth study to guide the construction. For example, there was not provided with quantitative relationship between bond strength and various factors, without considering the impact of shear strength and aging of bonding layer, lack of experimental research on bonding behavior under the condition of freezing and thawing, etc. In this paper, the major contributions were summarized as follows by experimental research and theoretical analysis.(1) Damage type and stress demarcation point of adhesive layer of XPS insulation board were summarized under the condition of axial tension. According to a large number of experimental data, this paper analyzed the relationship between the tensile strength and bond area and bond thickness. Based on the results of analysis and integrated with operational processes in engineering, optimal bonding thickness was proposed, which provided theoretical basis for the application of XPS insulating boards bonding.(2) This paper studied the bond behavior of XPS insulation boards and structure layer, the results showed bonding behavior varied with the bonding area, bonding method and thickness. The multivariate fitting method of shear strength was proposed. Based on experimental data, via least square method, the multivariate relationship between shear strength and these variables was proposed, which provided theoretical basis for the application of XPS insulating boards bonding.(3) In order to study the influence of freeze-thaw cycles on adhesive strength between insulation board layer and the structure layer, rapid freeze-thaw cycle tests were carried out on specimen according to the relevant specifications. The specimens with 0,10,20, and 30 freeze-thaw cycles was tested. The test results showed the relationship between shear strength and freeze-thaw cycles under the condition of different board size. Based on experimental data, via least square method, the quantitative relationship between shear strength & shear strength loss and frequency of freeze-thaw cycles was proposed.(4) Freeze-thaw cycles were the main factor of leading to the degradation of bonding mechanism. This paper mainly studied degradation of the bonding mechanism between XPS insulation board layer and structure layer from the angles of chemical and physical effects and proposed the conception of embedded effect. Chemical effect mainly included Van Der Waals force on surface and diffusion and binding on surface. Physical effect mainly included mechanical friction. The mathematical model of the degradation of the bonding mechanism under freeze-thaw conditions was proposed.