Experimental Study On The Water Damage Of Semi-rigid Base Materials

Because of the high strength and large carrying capacity, semi-rigid base has obtained the extremely widespread application in our country. At the moment it is the one of most widely used pavement structure type in the high grade highway. However, due to the overload and various kinds of natural factors, many senior highway opened to traffic in one or two years has produced water damage. This leads to these problems of poor durability and the early damage of pavement structure are becoming increasingly prominent. All these greatly have shortened the service life of the road and severely weakened its using performance. At the same time, the water damage has also brought huge economic losses to China and blocked the further popularization of the semi-rigid base asphalt pavement structure’s application technology.Therefore, it has the great significance that scholars do further study of the mechanism of water damage, the influence factors and evaluation methods of semi-rigid base materials. So that they can improve the water stability of the semi-rigid base materials and increase the water damage resistance of the pavement structure. This paper mainly studies the water stability of semi-rigid base materials:First of all, through to the domestic and foreign research on the water stability of semi-rigid base materials, this paper proposes a new method of measure to washout test on the stability of semi-rigid base materials. It can be better able to study water damage in the process of material damage.Secondly, according to the scouring test demand, it determine test size and sample producing method, sequentially complete the mix proportion design of washout test.Then, it does the scouring experiment of semi-rigid base material. Through the analysis of test data, the study found that:The washing action of high hydrodynamic pressure is the direct cause of water damage of road semi-rigid base material. The greater the hydrodynamic pressure value, the more serious the damage to the specimen. Under the same condition, hydrodynamic pressure value largely depends on the confining pressure and axial compression. As well as the greater the confining pressure and axial compression, the greater hydrodynamic pressure. The specimen damage of high hydrodynamic pressure mainly occurs at the beginning of the scouring test and with the increasing of scouring time it reduces. Under the condition of same scouring, the longer the specimen health age, the stronger ability to resist water damage. Finally, based on the above research and considering the reality of the actual road, it puts forward the main technical measures to improve the water stability of semi-rigid base materials.