The Research And Applicatoin Of High-performance Micro Expansive Concrete

Water loss is rather bigger when the agricultural water is transporting and distributing, especially in the north of seasonal frozen soil area in winter,because of the effect of negative temperature channel lining of frost heaving damage is serious, canal seepage control project quality is difficult to guarantee. Developing a high ability which has the anti cracking and anti seepage ability in channel lining concrete materials is particularly important for canal seepage control.The paper based on the mechanism of compensation shrinkage concrete, according to the idea of contraction and expansion phase offset,takes the shrinkage characteristic of concrete as the key point of study, combined with channel lining concrete environment, developed a restricted shrinkage coefficient expression of the concrete in canal lining under the many influence factors. Inorder to improving the limited expansion ratio and the tensile strength of concrete, appling the five yuan quadratic orthogonal rotation combination test, acpuiring the law of influence among expansive agent, fly ash, water reducer and polypropylene fiber on the limit expansion rate of concrete. Developing a high ability canal lining material with the set of anti cracking and anti seepage in one body, the specific research results are as follows:(1) Exploring the concrete shrinkage regular which is affected by the raw materials, construction technology, structure size, maintenance situation and working time.and giving a concrete shrinkage multiple coefficient expression. Considering the influence of frictional force between the soil of channels foundation and concrete lining, puts forward the channels lining compensation mode which using the shrinkage compensating concrete’s stress compensation and displacement compensation.(2) With the increase of the fly ash’s mixing amount, the restrained expansion rate increases first and then reduces, the last it begans to recover. The splitting tensile strength increase first and then decrease, basic in a low stable state, and finally get the optimum content of fly ash is 30%. With the increase of dosage of polypropylene fiber, the splitting tensile strength increased first and then decreased, the restrained expansion rate is first increases then decreases. When the mixing amount of polypropylene fiber is 1.575 kg/m3, the compensation effect is perfect, and it has a better expansion.(3) Appling orthogonal experimental study the tensile property of double expansion source concrete which affected by the water cement ratio, sand ratio, the dosage of fly ash and water reducer. The variance analysis results show that the water cement ratio, the dosage of fly ash and water reducer have a significantly effect on the mechanical property of shrinkage compensating concrete, the sand ratio has no effect on the contrary. Eventually acquired the water cement ratio, fly ash and water reducer’s optimal dosage is 0.55, 25% and 0.55% respectively, and getting the double expansion source concrete’s ultimate tensile value and tensile strength.(4) Appling the five factors of quadratic rotation orthogonal experiment, studying the influencement ofconcrete’s restricted expansion rate which is affected by UEA-S, magnesium oxide, fly ash, water reducer and polypropylene fiber, got the the regression equation of concrete’s compressive strength, splitting tensile strength, limit expansion ratio respectively by using the regression analysis. Through the regression equation can predicte the strength and restricted expansion rate which can meet the engineering requirements.(5) Based on the seamless design theory, discussing the reasonable spacing of channel expansion joint, giving the calculation formula of expansion joint distance and the rationality of theoretical formula is verified by engineering example.