Study On Application Of Shrinkage Compensating Concrete In Seepage Control Of Irrigation Canal

The concrete in seepage control of irrigation canal is one of the most widely used technologies. The uppermost problem is the crack in canal lining concrete. Many examples of engineering project indicate that, the cracks which caused concrete shrinkage will decrease the mechanical performance of concrete, affect the using life and water-tight and water conservation of canal. At the same time, the crack will cause the economic lost. The thesis analyzed the research result of predecessor,made use of the second-degree polynomial regression analysis and orthogonal rotation design to arrange the experiment, researched The law of influence of concrete on expansion ratio and mechanical property, discussed the application feasibility of shrinkage compensating concrete and design of super-long reinforced concrete structure for impervious channels. Main results are as follows:(1)The thesis analysis the main effect,single factor effect and the interaction effect of each factor .Fly-ash was the remarkable factors,It as mixture in concrete can decrcase the water quantity, suppress the concrete shrinkage. At the time, the pozzolanic effect of fly-ash could make C-S-H sol-gels which could fill the pore structure. So fly-ash could compensate the concrete shrinkage.(2)The crystal of ettringite is the product of expansive agent and cement hydrated and consolidated in compensation shrinkage concrete project. As a result these water-absorption crystals will cause the concrete micro-expansive. The compensation shrinkage of concrete has the best effcet , which the admixture of expansive agent is appropriate.(3)The relationship between water-cement ratio and expansive of the concrete is rather complicated. Water-cement ratio could affect the hydration process and strength devlopment of concrete. The experiment results indicated that, an addition of 10% expansive agent, 40% fly-ash and water cement ratio 0.4, is the optimum admixture.(4)We had to solve the problem of concrete shrinkage and have few post-poured strip of concrete canal. The no-seam design and construction of super-length concrete structure is a new-typed of design and construction method. The article stated the principe of compensated shrinkage concrete, discused the theoretical and meaning of no-seam design and construction of super-length concrete structure; proposed the designing methods of expansive belt and tectonic measures. We could use super-long structure's joint less design and expansion joint to achieve the stress compensation. Finally,the thesis proposes the principles of installing expansive belt and widening spacing of expansion joint.