Study On The Substrate Processing System On Beijing -Shanghai High Speed Railway Bridge Polyurea Project

Under construction in the Beijing-Shanghai High Speed Railway is the first time since the founding of New China, the longest mileage-building, the largest investment and highest standards of high-speed railway, and its full line of polyurea protective coating technology as their waterproof layer, which has become the largest project so far. Substrate processing system plays a significant role on polyurea project. According to the local environment and climate characteristics, epoxy substrate processing system for construction of the shortcomings in the winter, putting forward the application of new polyurethane type substrate processing system (QTECH-112 system), study characterization and physical properties of materials. For polyurea layer of a large area off phenomenon, from the perspective of the substrate processing system, study the static strain changes. Compare with epoxy system and parallel analysis with both. The following major elements:Firstly, comparative analysis QTECH-112 system and the epoxy substrate processing system, under different circumstances dry time and drying time. QTECH-112 system meets less than 4hours on GB/T-1728. The epoxy system dries time more than 4hours, drying time more than 24houes.Secondly, the study of the indoor and outdoor environmental factors, the epoxy substrate processing system and QTECH-112 System substrate adhesion and adhesion strength of polyurea tested. The results show, QTECH-112 System, indoor, 1day is 3.3MPa, 18day is maintain about 8MPa;outdoor,1day is 2.08MPa, 18day is maintain about 4MPa. The epoxy system, indoor, 1day is 5.14MPa, 18day is maintain about 8MPa;outdoor,1day is 1.88MPa, 4day is maintain about 6MPa. Adhesion strength of polyurea tested show, The epoxy system, indoor, 3day is 4.48MPa, 14day add to 6.23MPa;outdoor,3day is 5.81MPa, 4day down to 4.97MPa; QTECH-112 System, indoor, from 3day to 14day, adhesion from 3.59MPa add to 5.88MPa,outdoor, adhesion from 3.5MPa add to 4.04MPa.Thirdly, study QTECH-112 system, the thickness of the adhesion substrate has a certain impact. The following primer thickness is 2mm higher than the adhesion of more than 2mm.At the same time for testing the adhesion of the gel substrate analysis. The results showed that the modified acrylic adhesive measured value is far less than the epoxy glue; it is not suitable for QTECH-112 System.Fourthly, study temperature change on the adhesion of polyurea, the result shows QTECH-112 System and the epoxy system both have affect by low temperature in early time, later days substrate adhesion increase to normal temperature.Fifthly, the use of rapid freeze-thaw method, the measured dynamic elastic modulus epoxy system 125 times dropped from 71.05% to 44.80%, while the QTECH-112 system 75 after having been broken, dynamic elastic modulus from the modulus 15.21% down to.86.42% .Sixth, the use of static strain experiments on glass and marble on the board, epoxy primer and QTECH-112 system, high temperature, room temperature and low temperature static strain results. Studies show that the glass above the strain on the epoxy system high than on QTECH-112 system, and the shrinkage strain at low temperature -20℃is 650, far higher than the shrinkage strain is 140 on QTECH-112 ; marble slabs on the static strain experiments show that at room temperature and high temperatures, both with smaller micro-strain, after 8 hours in low temperature , the shrinkage strain increased to 300; changing the direction of change of principal strain, and QTECH-112 system has a relatively low micro-strain, and remained the same principal strain directionFinally, study QTECH-112 system adhesion on construction site and construction technology. Calculate the weight per unit area. From the perspective of Adhesion performance and economic costs, the way of substrate processing should be mild Shot peen. Introduce the QTECH-112 system in the Beijing-Shanghai high-speed railway construction in the autumn and winter application, compare with the difficulties of the epoxy system in winter.Through this experimental study and construction applications, as in the construction of the Beijing-Shanghai high-speed rail polyurea protective project, providing a scientific and reasonable test data for QTECH-112 system in the high-speed railway field of application.