Study On Concrete Freezing-thaw Resistance And Carbonation Resistance In Northern Shaanxi Region

In recent years, the problem of the durability of the concrete structure increasingly attracting widespread attention. In northern Shaanxi area morning and night temperature difference is big, the durability of the concrete structure mainly for freeze-thaw damage of concrete and concrete carbonization. In northern Shaanxi region, this paper based on the concrete structure as the object, through concrete in indoor test and field exposure test quickly, in northern Shaanxi region surrounding the freezing-thawing resisting and carbonation resistance of concrete was studied. The main contents are as follows:Combined with the fast freeze-thaw test and field exposure test, studied the different water-cement ratio and different dosage of fly ash on the concrete freezing-thawing resisting the influence of the performance, set up indoor laboratory quality loss rate, the relative dynamic elastic modulus and the cube compressive strength loss rate model along with the change of freeze-thaw cycles. Combined with the temperature, climate and humidity in northern Shaanxi region, it is concluded that the average annual freeze-thaw cycles, established the equivalent indoor laboratory annual average equivalent freeze-thaw cycles, and probes into the concrete frost resistance durability life prediction. Experimental results show that under the effect of freeze-thaw cycle the quality of the concrete, the relative dynamic elastic modulus and compressive strength are reduced gradually with the increasing of water-cement ratio and dosage of fly ash, concrete frost resistance performance and the decrease of the compressive strength.By rapid carbonization test indoor and field exposure of northern Shaanxi carbonization test, carbonation depth of concrete was studied with the change rule of carbonization time, analyzed under different water-cement ratio and dosage of fly ash concrete carbonation regularity and carbide development equation is established. The results show that with increasing of water-binder ratio, the dosage of fly ash and the carbonation depth is larger, and the good performance of carbonation resistance of concrete is reduced significantly. Through indoor test and field test results contrast analysis, obtain rapid carbonization test and indoor scene of northern Shaanxi natural exposure test. The relation between carbide.Carry out the coating concrete interior fast freeze-thaw cycle test and rapid carbonization test, studied the four supporting layer of epoxy coating and coating of silane antifreeze harmony will effect the performance of carbonation resistance of concrete. The test results show that the coating after these two kinds of coating, the antifreeze performance and carbonation resistance of concrete are improved, four matching epoxy coating layer of ascension work best.