Study Of The Influence On The Low Temperature Performance Of Rubber Asphalt Mixture Gradation And Air Void Ratio

Cracking of asphalt concrete pavement is a common problem around the world, there are many factors that can cause pavement cracking, one of the most important factor is the function of temperature that we talk about frequently. When temperature drop, asphalt layer can produce contraction deformation due to temperature difference, because of the asphalt pavement without setting shrinkage joint, the low temperature deformation will be base on the frictional resistance and the pavement infinite connection plate effect on shrinkage deformation of the constraint body, causing the tensile stress that is generated on the surface of the asphalt, which can lead to the generation of cracks. On rainy days, because of the existence of cracks, the water flow into the pavement structure, undering the action of vehicle load, which will lead to reduce and shorten the service life of pavement structure bearing capacity. In addition, with the improvement of people’s living standard and the development of automobile industry, the number of waste tires also proliferated, therefore, how to seek a way to kill two birds with one stone, which can not only improve the performance of the asphalt surface temperature.but also can burn waste tyre that can protect the environment, has become the focus of attention. One of the measures is that we incorporation waste tires into rubber powder as a kind of modified bitumen agent applied to the asphalt pavement, which has achieved good results.The porosity of Asphalt mixture has greatly influenced the mainly technical indicators of asphalt concrete pavement, which the size of the porosity directly relate to the asphalt roadbed drainage, rutting resistance, low temperature crack resistance and other related key technical indicators. At the same time, some research has shown that the porosity and the strength of the asphalt concrete pavement has a lot to do. Therefore, we must effectively control the porosity of Asphalt mixture when we design asphalt pavement.Existing experiments show that the 70 # ordinary asphalt as the matrix asphalt, rubber powder selected 40 purpose, under the dosage of 15% preparation of rubber asphalt, can produce excellently road performance. In order to study the voids affect the performance of rubber asphalt mixture at low temperature, this paper adopts the SMA- 13, AC- 13, Type B size distribution of the three types of rubber asphalt mixture. By controlling the Marshall compaction times and rutting specimens of rolling times, We can prepare different test specimens for different air voids., in turn, which We can perform cryogenic fracturing experiments and low temperature bending test, the test temperature is-20 ℃,- 10 ℃ and 0 ℃, 10 ℃. Test results show that, although in some test temperature conditions, the void fraction of low temperature performance of rubber asphalt mixture effect is not obvious, but in other temperature test, under the same level with different void fraction of rubber asphalt mixture performance in low temperature showed obvious difference.Both low temperature splitting test and low temperature bending test, SMA- 13 rubber asphalt mixture under different void fraction of the low temperature performance as well as the size of the order: 4% > 2% > 6% > 8%, AC- 13 rubber asphalt mixture under different void fraction of the low temperature performance as well as the size of the order: 2% > 4% > 6% > 8%. Type B rubber asphalt mixture are two kinds of test under the condition of the low temperature performance and diametral compression test, under the different void fraction of the low temperature performance as well as the size of the order: 11% > 13% > 15% > 17%, under the low temperature bending test, which the low temperature performance changing with the void fraction is not obvious.