The maximum and minimum dry densities are important parameters to evaluate the relative density of sand. This paper reveals the effect of particle breakage to the maximum dry density of calcareous sand

and analyzes the correlation between the characteristics of the maximum and minimum dry density and particle size

water content. Judging from the test results

test methods of the maximum and minimum dry densities are summarized and suggestions are drawn. The results show that dry density of calcareous sand firstly decreases and then increases. Particle breakage occurred in the maximum dry density test

which increases the test result of dry density. The amount of particle breakage increases firstly and then decreases with grain size. The minimum dry density decreases with the increasing of particle size; and the minimum dry density is affected by gradation and water content. The maximum dry density of calcareous sand should be tested by electric relative density meter is recommended; and the minimum dry density should be tested by measuring cylinder method.