A Performance Study On The Mechanial Properties Of Rubber-filled Concrete

As worn-out rubber tires increase each day, recycling of the wasted tires has become a hot issue. Studies have suggested that grinded tires that are mixed in concrete can promote the performance level of concrete.In the study, used tires are processed into grains under 5mm, and then isometric rubber grains take sand’s position at certain proportion in making concrete. The experiment adopts a trio cross-over plan of different ratio of water cement, different percentage of rubber grains, and different size of rubber grains. The conclusion is based on a 28-day experiment study of mechanical property, elastic modulus and impact strength of cements made at varied water cement ratios, varied grain percentages and varied grain sizes, as well as the influence on the relationship among those different factors, through trial mixing, molding, and maintaining.The results first show that the rubber grains help reduce concrete compressive strength and splitting strength compared to those of the benchmark specimen. The test results also find that the percentage of rubber grains added has greater influence than that of the size: under the same type of grain size, with the increase of the percentage of rubber grains mixed in, the rubber grain concrete aged at 28 d shows a reduced tendency in terms of compressive strength and splitting strength; under the condition of the same percentage of rubber grains, the rubber grain concrete aged at 28 d tends to fall in terms of compressive strength and splitting strength as the size shrinks.The study also confirms that the air content of the concrete increases significantly with the increase of the amount of grains added in, and the smaller the grain size, the greater the amplitude of air content; the elastic modulus of the concrete greatly decreases compared to the reference concrete, and the elastic modulus of the rubber grain concrete on day-28 is influenced the most by the percentage of the grain, the more added, the lower the modulus turns.Lastly, a good relationship is found between water cement ratio and impact strength: low ratio help improve the endurance of the concrete; however, there is a limit, because enough water is needed to ensure the workability in the process of construction. With the increase of rubber grain percentage, the abrasion resistance of the concrete rises first and then falls. The anti-abrasion strength peaks as the percentage of the rubber grain is 15%; it is even lower when the percentage is at 30%. And the best anti-abrasion strength comes out when the rubber grain size ranges from 2.36 mm to 4.75 mm, namely, the smallest unit of abrasion loss.