The Studying Of Early Adhesive Property Test Method On Chip Seal

Chip Seal mainly used as pavement surface layer, it uses special equipment to crisps and paves the gravel and bonding materials which must be meeting the relevant technical requirements on the pavement, then immediately rolling with rubber tire roller, make the gravel deeply wrapped inside the binder, forming a monolayer chip seal wearing course on the original surface. After Chip Seal treatment, the water seepage performance, wear resistance, skid resistance of the original surface are greatly improved. Because of its Ease of construction and economy, Chip Seal has been a major technology for road preventive maintenance domestic and foreign.The main diseases of Chip Seal is flaking and weeping rock, the gravel falling off is the main forms of the Chip Seal's early disease, and the main reason is the performance of early bonding. Our standards have not yet involved in relevant test evaluation method. The bonding performance between aggregate and asphalt blinder affect the quality of Chip Seal directly; the main reason of gravel falling off is the bad bonding performance between them. This paper first make an analysis of the mechanism of adhesion between gravel and emulsion asphalt, and then summed up the factors that affect the bonding performance of chip seal.For the detection and evaluation of early bonding layer of gravel seal performance, the paper Learns from Vialit and Sweep test, does some modification to the two test methods. In the Vialit trials, Several aspects such as balls falling methods, test board processing, curing temperature, water and load were analyzed and improved. In the same time,the paper compared Sweep test with transformation Sweep test and the paper evaluated early adhesion performance considering both the two test methods. The role of water and load didn't reflect in the two previous test, in fact, the dynamic water pressure has a lot damage to early bond properties.Further, cohesion torque test was to used for evaluating the whole bond performance of the gravel sealing layer. The test is analyzed by changing the testing temperature (30℃,40℃,50℃) and time (15min,0.5 h, 1h,1.5 h) and fiber content (0,75g/m2) and pressure (0.288 MPa, 0.532 MPa,0.7 MPa).Some problems were analyzed in the test, such as the pressure head damage, data accuracy and test location, and the corresponding solutions were also put forward. Finally, the test results showed that early cohesion value was stable and consistent with the actual situation when the cohesion values was between 0.5N.S and 1.3 N.S.Therefore, this method could reflect the early bond macadam sealing performance.