Cryogenic Performance Of PTN Bitumen Polyurethane Joint Materials

In northern areas of China, the winter is very cold, The lowest temperature reached45 degrees below zero, water conservancy projects such as channels, aqueduct still used the traditional joint materials in the joint. That are prone to damage under the condition of low temperature, and cause huge economic losses. The PTN cryogenic performance of providing theoretical basis for its application in cold region. In this paper, the main content includes:(1) Studied the ratio of three kinds of PTN petroleum asphalt polyurethane joint material hardness, tensile properties and bonding performance from at the temperature from20 ℃ to 100 ℃. The results find that the hardness, tensile strength of the material content(increase and decrease, the elongation at break is increased.Under the same ratio, hardness,tensile strength increases with temperature decrease, elongation at break decreases, and in turn below 60 ℃, hardness, tensile strength and elongation at break with the temperature change, no longer appear "stagnation" phenomenon.On bonding strength as the temperature increased after decreased first, elongation at break of bonding has been reduced, and ultra-low temperature under the "0".Observed by SEM(scanning electron microscope) samples magnified 5000 times, from the microscopic mechanism to explain the above phenomenon.Hardness and tensile properties of the related relation in order to nondestructive testing method can be used to predict PTN materials tensile properties.(2) Fixed rate of PTN component A and component B is 1:2 adhesive tensile test blocks, choose A, B, C three kinds of different base test respectively.The three base are based on two components mixture of materials, thus the optimum selection of three base first test,get three base of optimal ratio of 1:3, respectively 1:1. 75, 1-0. 5.(3) Research on low temperature tensile bonding performance of different base block, the influence of the fixed rate of PTN component a and component b is 1:2 make adhesive tensile test block.Choose A base of the ratio of 1:3, ratio of 1:1. 75 B base ratio for1-0. 75 D base respectively after low temperature test cycle, low temperature(73 ℃, 30 D)continuous(73-73 ℃, h), room temperature(23 ℃, 720 h) after processing, the tensile bonding performance of the block.Found that group D base block under the low temperature cycle base tensile properties superior to other two groups, group B base block under the low temperature continuous tensile bonding performance better than the other two groups, group A base block at room temperature tensile adhesive performance is better than the other two groups.For after low temperature cycle, continuous low temperature and room temperature low temperature cycle after processing of PTN material electron microscopic scanning and energy spectrum analysis, explained from the microscopic view PTN materials under the lowtemperature performance as the reason, found under the normal temperature state materials evenly dense structure, showed good tensile bonding properties, low temperature condition material molecular chain to contract, material internal molecular arrangement to change, the unidirectional, show some material tensile adhesive performance is greatly reduced.Low temperature cycle is similar to the low temperature continuous state, but because of the interaction between the contact with the water circulation material at low temperature and hydrolysis, lead to further damage of material structure, show the adhesive tensile performance under relatively low temperature continuous state.(4) Use PTN materials on the basis of performance study based on the structure of the joint design of the concrete face rock fill dam will PTN materials used in the joint of the concrete face rock fill dam surface of the water.The combination of PTN materials in engineering application design a new type of construction tools.