Damage And Its Restraint Of Green High Durable Concrete Exposed To Freeze-thaw Cycles

Green high durable concrete (GHDC), was opened out as a new concrete on the base of in recent years Green high performance concrete (GHPC), the high-performance expansion concrete(HPEC), hybrid fiber-reinforce concrete(HFRC), which was not only a high-durability (high impermeability,high frost resistance and high attack resistance), high work and high economic applicability, but also to protect the environment and economize energy, benefit to sustainable social development.In this paper seven large series with more than 19 kinds of concrete were prepared. Firstly we choose GHDC optimized mix of classic and open out different grades of GHDC on the base of the outcome of the trial of plastic shrinkage cracks.The author carries through a trial of concrete durability aiming at the current developments in the freeze-thaw cycles, 35% of the external flexural stress, NaCl solution attack, MgSO4 solution attack,(MgCl2+Na2SO4) complex solution attack factors. The trial is a frost resistance test with single freeze-thaw, double factors role (freeze-thaw+35% external flexural stress,freeze-thaw+10%NaCl,freeze-thaw+5%MgSO4,freeze-thaw+5%MgCl2+5%Na2SO4) and multiple factors role(freeze-thaw+35% external flexural stress+10%NaCl,freeze-thaw+35% external flexural stress+5%MgSO4,freeze-thaw+35% external flexural stress+5%MgCl2+5%Na2SO4). The principal studies is the amount of mineral admixtures (fly ash, slag and silica fume), the water-cement ratio, attacking solution, external flexural stress, admixture (high-efficiency entrained air agent, expanders) composites, fiber hybrid reinforced concrete factors such as the impact and analysis of the freeze-thaw damage and inhibit the development of the law to contain the damage to the concrete experimental study of the laws.Main conclusions are drawn as follows:(1) 35% of external flexural stress accelerates the process of deterioration of concrete injury,the role of stress should be paid full attention to under the practical environment of using concrete.(2) The concrete freeze-thaw damage for double and multiple factors in the salt solution were lower than single to the injury factor; In different salt environment the concrete freeze-thaw followed by the length of life is:Complex solution (5%MgCl2+5%Na2SO4 )ï¹¥5%MgSO4ï¹¥10%NaCl.(3) Low water-cement ratio and the amount of mineral admixtures (fly ash+ slag+silica fume),in(freeze-thaw+10%NaCl and freeze-thaw+5%MgSO4) injury concrete under the inhibitory effect was not significant.In Single factor in the freeze-thaw,(freeze-thaw+stress),(freeze-thaw+complex solution) following attack, significantly improving the overall frost resistance concrete and attack resistance. Frost resistance concrete and attack resistance has been improved to a certain extent.(4) Admixture (expanders+entrained air agent) and the hybrid fiber-reinforced composites produced a composite effect of inhibiting the injury, concrete curb injuries are very obvious, the stronger resistance concrete, concrete anti-injury life greatly improved.(5) Through regression analysis of the experimental data the mathematical model of concrete is obtained by freeze-thaw damage and failure of the process of testing conditions.(6) In practical application, accordance with the characteristics of various measures, different measures for different damage environmental shoud be taken, such as mixing different additives, using the appropriate proportion of hybrid fiber to inhibit injury, is the best results.