Mechanical Property Deterioration Rule of Steel Slag Asphalt Concrete Under Hot and Humid Conditions
The steel slag coarse aggregate has poor volumetric stability with large variability,which could result in volume expansion and durability risk for steel slag asphalt concrete during long-term service period.For this purpose,the volumetric stability of steel slag coarse aggregate was tested by using autoclave test.Five different types of asphalt concrete were designed by using the single or hybrid addition of steel slag and diabase coarse aggregate.The asphalt concrete,prepared with diabase asphalt concrete and stabilized steel slag coarse aggregate after autoclaving,was used as the reference.This study investigated the volume expansion characteristics,indirect tensile strength,and fatigue resistance attenuation rule of steel slag asphalt concrete at 60℃ with different immersion periods.The prediction model of volume expansion rate for steel slag asphalt concrete was established based on the different steel slag contents and water immersion periods.The prediction models of residue strength and fatigue life were proposed due to the water immersion and steel slag content to analyze the mechanical property attenuation rule.The result indicates that the autoclave test can quickly examine the poor volumetric stability of steel slag coarse aggregate.After long-term water immersion,the indirect tensile strength,modulus and fatigue life of steel slag asphalt concrete show the obvious attenuation trend.The results obtained from indirect tensile strength and fatigue tests on steel slag asphalt concrete show the good linear correlation.By using the indirect tensile strength residual rate can quickly evaluate the service durability of steel slag asphalt concrete.The steel slag asphalt concrete volume expansion shows the exponential decay relations with strength loss,modulus loss,and fatigue life loss.The volume expansion destruction of poor quality steel slag particles has a decisive effect on the deterioration of mechanical properties of steel slag asphalt concrete.The steel slag stability should be controlled at the source and in material selection.
road engineeringmechanical attenuation mechanismlong-term water immersionsteel slag coarse aggregateconcretedurability
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