Optimization of test parameters for measuring aggregate adhesion by column lamp core method
In order to solve the problem of poor reproducibility of test results caused by the non-standardized test operation and test steps of the column wick method used in the aggregate surface energy adhesion test,six kinds of test liquids(chloroform solution,toluene solution,diiodomethane solution),weak polarity(formamide solution,ethylene glycol solution),strong polarity(distilled water)and aggregate powders from two kinds of sedimentary rocks(A limestone,B limestone)and three kinds of magmatic rocks(diorite,basalt,granite),which are commonly used as aggregates in pavement engineering,were selected for the columnar wick method test.Combined with the test principle and test phenomenon of the column wick method,the contact angle influence of the factors of powder vibration time,test liquid,aggregate powder particle size,and aggregate powder composite type was studied.The results show that the contact angle is significantly influenced by the roughness of the aggregate surface,and when compared with the contact angle experiment,the influence of roughness can be excluded by utilizing powder materials in the column wick method.The pore channel formed by aggregate powder is found to be most stable,after a vertical vibration height of 3 cm and a vibration time of 6 min in the columnar wick method.The larger the dispersion component of the test liquid accounts for,the larger the formation of molecular forces.This results in a progressively smaller contact angle with the aggregate powder,which is prone to unreasonable contact angle results and should be avoided.The particle size of the aggregate powder directly affects the measurement of the contact angle,and selecting a size of 0.5 mm is deemed optimal for contact angle measurement.Moreover,selecting powder with a particle size between 0.04 to 0.075 mm as test samples can reduce test operation errors and result dispersion,thus enhancing the repeatability and reproducibility of the column wick method test.Through the surface energy test of acid-base composite mineral powder,it is observed that alkaline stone powder is more readily adsorbed compared to acidic stone powder.8 tabs,10 figs,30 refs.
road engineeringaggregatecolumn wick methodsurface energy theorycontact an-glefactor analysis
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