Study On Durability Of Aeolian Sand Concrete Under Wet-Dry-Wind Sand Erosion

In recent years,greening the desert,people entering and retreating from the sand,and preventing and controlling desertification have become urgent ecological management issues in desertified areas in China.In order to change the research and development ideas,in order to transform the desert yellow sand into green water and green mountains,and green water and green mountains into Jinshan and Yinshan,this paper selects the aeolian sand in Ulanbu and desert of Inner Mongolia as fine aggregate.Aeolian sand replaces some river sand,and aeolian sand concrete with strength classes C20,C30,and C40 is prepared,and the aeolian sand concrete is thoroughly explored in a single aeolian sand erosion,a single dry-wet cycle,and the dry-wet-aeolian sand erosion coupling The durability problem and micro-pore characteristics under the action provide theoretical basis for the engineering construction of aeolian sand concrete under the sulfate environment in the wind-eroded area.The main research conclusions are as follows:(1)After the aeolian sand concrete undergoes a single dry-wet cycle or sulfate dry-wet cycle-wind-sand erosion erosion coupling,the proportion of multiple harmful holes increases significantly,and the characteristics of small pores to large pores exist in the concrete.After the aeolian sand concrete undergoes a single dry-wet cycle or sulfate dry-wet cycle-wind and sand blowout coupling effect,the cement slurry appears slender cracks and through cracks,and the sulfate and carbonate crystals generated by the chemical reaction adhere to the concrete pores.Which caused the concrete pores to develop into slender cracks and cracks under salt erosion.(2)In the whole process of aeolian sand erosion,the degree of damage of aeolian sand concrete to blowout pits is significantly greater than that of blowout gully.The main factor causing blowout damage of aeolian sand concrete is the normal stress perpendicular to the blown surface.The deterioration mechanism of aeolian sand concrete lies in the cement mortar hardness<aeolian sand sand hardness<coarse aggregate hardness.The shedding of the cement mortar layer exposes the coarse aggregate to the surface and affects the durability of the concrete.(3)According to the theory of the material decay equation,the endurance life of aeolian sand concrete under the action of aeolian sand erosion is 144 a,and the endurance life under the coupling effect of sulfate wet and dry-wind sand erosion is 125 a.According to the grey system theory,the less harmful holes of aeolian sand concrete under the effect of sulfate dry-wet cycle and aeolian sand erosion have the greatest impact on the 28-day mixed compressive strength;aeolian sand concrete under the sulfate dry-wet cycle-aeolian sand blowing The effect of harmful holes on the mass loss rate is the largest under the effect of corrosion coupling.