Research On Behavior Of Mechanical Properties And Chloride-penetration Resistance Of Concrete With Mineral Admixtures

Concrete structure with good structural properties bring economic and energy saving social benefits, has become a most widely engineering application. But in long-term bad erosion chloride environment effects,such as the destruction of the role of Seaport Wharf buildings subjected to wind waves, frozen and tide and other natural factors, road and Bridge Engineering in addition to ice salt surface spalling, increasingly serious environmental pollution caused by increased carbon dioxide concentration, acid rain increased, and so on, lead to concrete structure will appear the internal injury, the use of functional degradation or even failure of carrying capacity and other serious durability problems The concrete in chloride environment,chloride ion erosion performance has been the focus of concern in the field of engineering research,iss difficult to realize high performance concrete This paper from the concrete structure under chloride environment of surface spalling, corrosion and internal injury problems affect the structure durability to consider,proposed by adding fly ash (10%,15%,25%) and silica fume single doped (7%,9%,12%) equivalent to replace part of cement, respectively in the water, 4% sodium chloride solution,10% sodium chloride solution by flux and RCM diffusion coefficient experiment, to explore the different mineral admixtures on the resistance of concrete to chloride ion erosion performance influence mechanism.The main conclusions are as follows:(1) After incorporation of fly ash, concrete of 28 day cube compressive strength and splitting tensile strength decreased with increasing dosage gradually decreased and content to 10% fly ash added after this reduction is not obvious, different content of silica fume join to improve the concrete of 28 day cube compressive strength and splitting tensile strength, and the more content to improve the amplitude.(2) The mixing amount of the fly ash is 15% and 25% can effectively reduce the concrete electric flux and salt solution at a concentration of 0% and 10% of the fly ash content is 10% but increased flux, is not conducive to the resistance of concrete to chloride ion penetration Silica fume added greatly to reduce the concrete electric flux value and three different dosage.(3) Water binder than 0.38 concrete experience after 50 cycles of freezing and thawing cycles, 10% fly ash added in the salt solution concentration is 0% and 10% improve the concrete electric flux value; but along with the increase of silica fume quantity can significantly reduce the chloride ion flux and improve the more content of greater magnitude, is conducive to improving the impermeability(4) Water binder ratio is 0.38 silica fume concrete curing 100 days and 28 days standard instar period compared to reduce the value of the concrete electric flux, in 4% and 10% sodium chloride solution, dosage is 9% and 12% of wollastonite reduce concrete chloride ion flux amplitude roughly the same(5) The incorporation of different amounts of fly ash can reduce concrete chloride ion diffusion coefficient, on permeability have a positive role in improving resistance of 28d concrete chlorine ion; the addition of silica fume on chloride ion diffusion coefficient of concrete to decrease the effect more obvious, and there a maximum when silica fume quantity exceeds the value of concrete chloride ion diffusion coefficient and the influence is small...