Researches On Anti-crack Technology Of Hydraulic Massive Concrete Hydraulic Mass Concrete In Cold Areas

The large volume of hydraulic structures , the bad working environment , the changes of operation , all of these make us strict to the performance of concrete as the strength , the deformation , the endurance and so on . More and more engineering practice show that the crack issue of the concrete of large volume hydraulic structure become the major factor which effect the endurance , especially in cold areas . Domestic and international research show that the cracks of the structure are inevitable , but the degree of the harmful could be control if we used feasibly and effectice measures of the comprehensive prevent fissure . This paper based on the study of the large volume pier concrete of the PuShi-river hydropower station , we know the international technical index about large volume concrete in cold areas from the literatures in home and abroad . To solve question of refuse crack of large volume concrete in cold areas and determinate the technology routes and further discussion , analysis and determined the performance of the concrete mineral admixture and the admixture in this time , understand the effect of many kinds of the concrete admixture on long-term working . Determined the primary combining ratios of the large volume concrete in cold areas , performance function test on the different kinds of concrete from JiLin . Obtained the best combining ratios of the practical constructions what can be used in the pier of the PuShi-river hydropower station , and given the experiment performance datas of the combining ratios . The paper expounds the anti-crack mechanism of large volume concrete and made a microanalysis .The result of this paper is the impermeability grade and frost resistant grade of concrete mix ratios , all of them meet the design requirements . Especially , the anti-limit tensile is better than the normal concrete . As Fig.5-1 and Fig.5-2 . The most outstanding result of the test is that the comprehensive performance of the concrete which admixture combination by fly ash and expansion agent is better than the other concrete (emphasize anti-crack). The hydration heat peak of concrete changes relatively large , the hydration heat peak appeared at the early time is higher , but the peak of hydration heat occurred slowly and regression slowly too , this maybe caused by expansive agent . The hydration heat of this test with the mixture ratios is lower than normal concrete significantly . As the table 5-12 . The different from the research before is that the main results of this paper is the antifreeze resistance of the large volume concrete in cold area . The main study of this paper is analysis and solve the questions by the concrete itself , especially provide a effective reference for the measures of the concrete prevent fissure during the construction and the measures of concrete with the expansive agent UEA prevent fissure . Provide a powerful and reliable theory combining ratios of the constructions for the pier of the PuShi-river hydropower station and cracking resistance of concrete .