Attività

The putty-based composite silicone weather stripping extruded rubber strip was made up of Ethylene-Propylene-Diene Monomer polymer rubber (EPDM foam strip) and the external composite layer (putty paste) of high viscosity reactive polymer cement (butyl rubber). The primary reason for use of the composite was to take advantage of the external putty-based material’s properties of viscosity and superplasticity, which can heal mesoscopic cracks and defects on the surface of concrete structures to improve interface waterproof ability. Cross section dimensions and picture of the rubber strip are shown in Fig. 1.

Figure 2 displays the lateral confinement loading test device, which is composed of two parts: convex shape of the upper part and concave shape of the lower part. The inner and outer diameter of the annular groove was 170 mm and 220 mm, respectively. The upper part has protrusion that squeezes the strip, and the annular groove is set at the lower part of the device with an annular rubber strip installed in it (see Fig. 2c). The length of the EPDM foam rubber in the elastic state has 640 mm, and the compression area is 15,315 mm2. Quasi-stress control was selected for the tests.

Experimental results of the putty-based composite strip under lateral confinement for compressive stress and displacement are provided in Fig. 7. At the early stage of loading, the compressive stress of the composite strip gradually increased with the displacement. It was observed that the displacement dramatically increased and at the later stage of the loading when the load reached at 112.36 kN primarily maintained at 11 mm. At end of the test, the rubber strip was not crushed and the internal EPDM foam rubber after unloading almost recovered to its original shape. The maximum displacement of the putty-based composite rubber strip under lateral confinement was approximately 11 mm, which was brought on by the squeezing of the inner hole of the composite strip raising the internal pore of the EPDM rubber. The instantaneous elastic recovery during the unloading process was 85% of total deformation. The residual deformation of the composite rubber strip was gradually recovered to its original state with time. Eventually, the rubber strip was not damaged. The deformation recovery of the inner elastic material to its original shape can partly drive unrecoverable external putty material.