Experimental Study On The Long-term Performance Of Recycled Concrete Beams

With the development of society and economy, the construction industryunprecedented prosperity, but construction waste emissions increased year by year.The majority of construction waste is without treated and just only simply landfilled. Itis not only a waste of land and resources but also pollute the environment. Concrete isthe main construction materials. The waste concrete is growing quickly. So someresearchers begin to study the recycled concrete.At present, some corresponding technical achievements of domestic existing basicproperties of recycled concrete aggregate. But the study on long term performance ofrecycled concrete is not much Long-term Recycled concrete load tests with fourdifferent reinforcements have been designed to study the creep of the recycled concrete.The long-term deflection of the concrete beam have been recorded during thethree-year dead load analysis to study the creep, flexural deflection and crackdeveloping of the target concrete beam.The test results show that the crack developing of recycled concrete and ordinaryone are basically the same while the flexural deflection of the recycled concrete growsfaster than the ordinary one’s in the first year.300-days’ long-term flexural deflectionmakes up30%-57%of the short-term flexural deflection and it slows down in thefollowing two years. The increment of long-term flexural deflection in total three yearsis40%-111%of short-term flexural deflection. Different ratios of reinforcement canhave an impact on long-term performance of recycled concrete. The long-term flexuraldeflection of ordinary concrete with same size and reinforcement is then calculatedbased on related standards to compare it with the result of recycled concrete.According to the calculations, the long-term flexural deflection of recycled concrete isapproximately1.2-1.5times of calculated one. The increment of long-term straindeflection in360days is120%-160%of short-term strain deflection in the upper partof the beam while130%-180%in the bottom part.