Study On Mix Proportion Optimum Design And Durability Performance With Mold-bag Concrete In Hetao Irrigation District Of Inner Mongolia

With the development of social economy and the improvement of people’s living standard, The consumption of water resources will be more and more tremendous, This resulted agricultural water consumption be more nervous. In this paper, Starting from the view of water-saving irrigation and improving water use efficiency, Relied on the channel lining project with mold-bag concrete in Hetao Irrigation District of Inner Mongolia, experimental study on the mix proportion design of mold-bag concrete, by "Internal mixing" method, replaced cement with fly ash 25%、30%、35%、 40%、50% respectively, its frost resistance were studied, thus proposed that the appropriate mix proportion with mold-bag concrete in Hetao Irrigation District of Inner Mongolia. In this paper, the main work and conclusions are as follows:(1) Raw material testing from four locations, characters about raw material was grasped, this paper offers a reference for mix design, during the design process, referred mix proportion about serving mold-bag concrete and the results of sampling inspection, adding air entrained agent and water-reducing agent properly, improved the air content of mold-bag concrete to 6%, optimum design for original mix proportion.(2) Through experimental research of basic mechanical properties, it is concluded that the preliminary strength of specimens affected by a certain amount of fly ash, the strength was very close which fly ash concrete content as 25% and 30%, with the increased of fly ash content, the concrete strength was decreased, when the content reaches 50%, the strength has been unable to satisfy the design requirements.(3) By freezing-thawing cycle test, we can draw a conclusion that with the increase of the number of freezing-thawing cycles, mass loss rate increases first and then decreases, after 200 cycles of freezing-thawing cycles, specimens has a good surface performance, the mass loss rate of concrete with fly ash 25%、30% were not more than 5%,relatively dynamic elastic were negative correlation with the number of freezing-thawing cycles, after freezing-thawing cycle 200 times, the relatively dynamic elastic decreased dropped to 60% which fly ash content was 50%, compared the mass loss rate with the relatively dynamic elastic, the air-entrained agent added, the integrity of concrete be improved obviously, freezing-thawing damage mostly effect on outer surface, by pore structure evolution test, analyzed from the view of micro aspects on frost resistance of concrete, the results obtained were in agreement with the results of freezing-thawing cycles;(4) According to the results,200m test section has been pouring with mix proportion of 25% fly ash concrete, and it has verified the feasibility of the experimental scheme.