Influence On The Durability Of Concrete Pavement In Different Deicing Salt Freeze-thaw Environment

Nowadays infrastructure construction develops vigorously, cement concrete are usedheavily in roads, Bridges, airports, docks, construction engineering, etc. In order toguarantee the traffic running normally in winter, snowmelt agent (de-icing salt) is widelyused. At present,deicing salt included a wide range of items on the market, from NaCl,CaCl2, Ca（COOH）2,Mg（COOH）2, ethylene glycol etc. Different deicing salt on theextent of damage of pavement concrete is different, the erosion mechanism is different,have different degree of pollution on the ecological environment. So, research concreteunder different de-icing salt environmen, the frost resistance durability of concrete is ofgreat significance.Based on test method for rapid freezing and thawing for ordinary concrete, analysis ofdifferent salt solution (NaCl and CaCl2, CMA (calcium magnesium acetate), Na2SO4) andtheir different concentrations (0%,3%,6%,12%,25%) influence on resistance tofreezing-thawing of concrete. It is concluded that the change rule.of mass loss, relativedynamic modulus of elasticity and compressive strength of concrete cube,under theenvironment of the salt frozen concrete.In NaCl salt freezing, with increasing the number of freeze-thaw cycles, Concreteblock surface was stripped material gradual seriously, the relative dynamic elastic modulus,cube compressive strength decline gradually. Concrete block was frozen in3%NaCl salt,destroyed most seriously, after100times of freeze-thaw cycles,mass loss at7.55%, therelative dynamic elastic modulus at13.34%, down60%cube compressive strength ofconcrete. Concrete durability are similar in NaCl and CaCl2salt frozen environment,CaCl2salt frozen on the erosion of concrete is small; Second, different concentrations ofCMA, under the same number of freeze-thaw cycles, arrange concrete state from good tobad for:25%CMA＞12%CMA＞6%CMA＞3%CMA;Again, Na2SO4not easily soluble inwater, salt frozen only50times, relative dynamic elastic modulus decreased to less than60%. After100times,coarse aggregate exposure, a sharp increase in mass loss, relativedynamic elastic modulus is only20%.Through the test comparison of four kinds of salt, concrete freeze-thaw damage ismost serious in3%concentration of salt solution. The higher solution concentration, the better durability of concrete. Concentration of3%, for example, resistance freezing–thawing of concrete in the order:CMA>CaCl2>NaCl>Na2SO4(">"mean" better than").According to the quantitative analysis of concrete frost resistance, Using MATLABnumerical analysis software to fit out empirical formula about concrete under differentconcentration of NaCl salt frozen environment maximum number of freezing-thawingresisting. Provide certain reference for the research of concrete salt freezing, the use ofroad de-icing salt has a guiding significance.