Roads and Bridges - Drogi i Mosty
15, 1, 2016, 5-20

Evaluation of the two methods of determining bulk density of sand: tapping fork test and vibrating table test

Waldemar St. Szajna Mail
University of Zielona Góra, Faculty of Civil Engineering, Architecture and Environmental Engineering; Prof. Z. Szafran 1 str, 65-516 Zielona Góra
Paulina Lechocka Mail
University of Zielona Góra, Faculty of Civil Engineering, Architecture and Environmental Engineering; Prof. Z. Szafran 1 str, 65-516 Zielona Góra
Published: 2016-03-31

Abstract

The aim of this research is to compare and evaluate the methods used for determining the maximum bulk density of sand ρdmax. Two methods were considered: tapping fork test and vibrating table test. They were compared in terms of the efficiency of compaction and the repeatability of results. The tested material was quartz sand. The tapping fork test was carried out independently by two lab workers. While the tapping fork method proved to be satisfactory in terms of compaction efficiency (as demonstrated by the mean bulk density of ρdmax=1.805 g/cm3), it was not as good in terms of repeatability (3.35% of relative error) and showed sensitivity to human factor. The second test was performed using a vibrating table with inertial excitation. Selecting an appropriate frequency of vibrations proved to be a key factor. Too low frequency resulted in poor compaction and in case of too high frequency the density was increasing and decreasing alternately. The frequency of 39 Hz was found to be the optimum value, producing the average density of ρdmax=1.795 g/cm3 and 1.56% of relative error after vibrating for the standard time of 12 minutes. Even seemingly small variations of relative error between the analysed methods resulted in considerable variations in the degree of compaction of the tested sand. Therefore, the selection of the method is so important due to the criterion of test objectivity.

Keywords


bulk density, tapping fork, test method efficiency and repeatability, vibrating table

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References


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Evaluation of the two methods of determining bulk density of sand: tapping fork test and vibrating table test

  
Szajna, Waldemar St.; Lechocka, Paulina. Evaluation of the two methods of determining bulk density of sand: tapping fork test and vibrating table test. Roads and Bridges - Drogi i Mosty, [S.l.], v. 15, n. 1, p. 5-20, mar. 2016. ISSN 2449-769X. Available at: <>. Date accessed: 09 Jul. 2020. doi:http://dx.doi.org/10.7409/rabdim.016.001.