Influence of Recycled Concrete Strength on Fire Resistant Performance of Tubular Structures

The fire-resistant performance of recycled concrete member was studied to further promote the application of recycled concrete.Two concrete tubular structure models with different concrete strengths were designed and tested under both vertical load and high temperature according to the standard heating curve in the test furnace.The two models were made from recycled concrete with both the coarse and fine aggregate replacement rate of 100%.Their recycled concrete was specified as C20 and C30,respectively.The fire endurance,temperature field,failure characteristic,wall deflection and vertical displacement were comparatively analyzed.The recycled concrete temperature field of the specimens was also simulated by running ABAQUS software and they agreed well with the experimental results.Resultsshow that with the increase of the strength of recycled concrete,fire endurance and fire resistance of the tubular structure decrease and the structure tends to fail in expansion under high temperature.