Research On Performance Of New Joint Sealing Material In Seepage Control Engineering

Canal seepage control plays an important role in our China Agricultural Water Saving Irrigation, and the integrate level of canal seepage control engineering is low, especially, for the techniques of canal expansion joint. The leakage in the joint of seepage control engineering is still a serious problem, which has not been paid enough attention to. In the dissertation, we focus on the problem of the property of a new type of concrete canal joint material (PTN) is unclear, whose application results are satisfactory. The main research content of the dissertation involves: theoretical analysis of concrete canal expansion joint design, tensile property of different mixed ratio, density analysis of different mixed ratio, curing process, effect of primer, thermal aging property, antifreeze characteristic, tensile property of bonding between joint material and different base material, moreover, we discuss a new method using in material tensile proporty analysis.A comparatively systematic study has been carried out on its property, based on many experiments. The research can provide theoretical foundation for further study and application; it also can offer technique support for production and construction.The main conclusion is listed as follows:1,Theoretical analysis indicates that theoretical width value of the concrete canal expansion joint is 14.8mm, theoretical distance between joint is 16.25m～25.25m. According to the property of material, we suggest adjust the provision in standard for engineering technique of seepage prevention on canal properly, width of joint values 20mm(Standard : 20mm~30mm), distance between joint values 15m~20m(Standard : 15m~20m).2,According to the analysis of the joint material tensile property, the mixed ratio of 1:1, 1:2, 1:3 are all satisfied with the demand, considering with the analysis of cost, ratio of performance to price of the mixed ratio 1:2 is higher, meeting with the demand of irrigation canal engineering.3,The curing of PTN is fast, generally speaking, PTN stop flow to initial condensation after 1 hour, and the joint material can meet with demand of water transferring after 24 hours. Tensile strength increases with the time passing. After 3days the tensile strength increases to 0.2MPa, reaching to the 30% of total strength, after 15 days the tensile strength increases to 0.41MPa, reaching to the 61% of total strength, after 30 days the tensile strength changes little, and climbing to the total strength 0.67MPa. The change of deformability is not significant during the curing process, the lowest elongation at break is 357.48%, the highest is 566.47%, and the joint material can bear the demand of deformation of canal.4,The tensile property of PTN is satisfactory, and can meet with the demand of the irrigation canal engineer. Using the primer can enhance the tensile property of joint material, we can use the primer in some engineer demanding high quality, but using the primer also increases the cost. For general engineer, we suggest not adopt primer.5,Both of the thermal aging property and antifreeze characteristic of PTN are good, it can be used under high temperature, in cold region. By the heating treatment of 70℃for 30 days, the tensile property decreased, but the joint material also has high deformability, the elongation at break is 149.76%, at the same time, the tensile strength changes little, is still 0.67MPa. It does not show the phenomenon of flowing under high temperature, losing joint function. After 200 times freeze-thaw cycle, we find that the tensile strength of material shows downtrend, but the decreased tensile strength is 0.36MPa, it is also higher than the specified value 0.2MPa in standard. The elongation at break also shows downtrend, the decreased elongation at break is 150%, it still can meet with the demand of canal deformation. On the other hand, we find adding appropriate additive can ameliorate material performance, the material with the smallest decrease of tensile strength has been decreased by 5% only, compared to control, which adds 10% fly to the material.6,Bond property between PTN and different base material, such as wood, concrete, marble, , glass is good, This material can be applied to the other application fields. The test result of bond property is: wood>concrete>marble>steel(rustiness)>glass>steel(rust removed).7,The concept of tensile failure work is put forward, though, the concept relates the stretching force and elongation indicator, it still demands more detailed and deeper inquiry, if we want use it to appraise the canal joint material, instead of tensile strength and elongation at break.