| The dam-building technology of MgO concrete, which bases on the research product of MgO concrete means that moderate tailor-made MgO expansion agent can be used for the production of hydraulic dam concrete, and its own delayed micro-expansion characteristic can be used for compensating concrete shrinkage for temperature fall and improve the crack resistance of concrete itself. The technology commences on accommodating bulk deformation of concrete so as to compensate temperature deformation of concrete, which gives up the traditional theory of concrete crack prevention by controlling concrete temperature. The dam-building technology of MgO concrete is firstly applied to the deep foundation groove concrete of main works of arch dam of Dongfeng hydropower station in Guizhou Province(added up to 1.36×10~4m~3) and the result turns out a success, which makes a contribution to popularization of the technology. In the article, the test result of mechanics performance and deformation performance, and nearly 10-year site observation result of MgO concrete are analyzed, and it shows that mechanics performance of MgO concrete excels common concrete, its long-tern expansion deformation has favorable delayed micro-expansion characteristic which corresponds to mass concrete with the characteristic of slow dissipation and slow shrinkage for temperature fall. The engineering practice proves that the using of dam-building technology of MgO concrete with some other assistant appropriate measures can replace the traditional temperature-controlled measures of concrete dam partly or completely(such as no-cooling by water pipe , no-mixing round with ice, and so on ), and it can solve problem of crack prevention of hydraulic dam concrete effectively. Meanwhile, it can achieve long blocks, thick layers, open silo, all-weather continuous concrete pouring so as to expedite the construction rate of progress and economize engineering investment.
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