Experimental research on compaction characteristics of aeolian sand

Unlike the other road materials,aeolian sand had some compaction characteristics that were key factors of influence on construction qualities of highway in the desert.In order to study the characteristics,a series of laboratory and field tests were performed,which included the experiments of sieve analysis,modified standard compaction,vibrating compaction and field test.By analyzing the sieve analysis test data,it was found that the gradation of aeolian sand was bad,with even fine grains with diameters mostly ranged from 0.25mm to 0.074mm.Then,based on the laboratory compaction test results,a compaction curve was plotted,which was quite different to the other kinds of road materials,and similar to a horizontally-written letter S.There were two peak values in the special curve with the increase of water content,which was the special character of aeolian sand could be well compacted whatever it was dry or wet.Also,according to the laboratory vibrating test results,the best vibrating frequency range was proposed,which was from 45 to 50 Hertz.Moreover,some field compaction tests were carried out.On the construction site of highway,the aeolian sand subgrade was compacted in the condition of natural water content,with optimized construction machines,obtain an acceptable degree of compaction,96%,meeting the current specifications.At last,comparative studies were carried out with electron microscope pictures of aeolian sand,which indicated that the microstructure of compacted dry aeolian sand was much denser than that of natural one.