Experimental Characterization of Shape of an Aggregate by a Numerical Value—Application to Senegalese Basaltic Aggregates for Rail Transport

摘要

This article first talks about railways in general and ballast in particular. An inventory is then made on the modernization of the Senegalese ballast railways. In the second phase, an experimental work of characterization of basaltic aggregates of Diack (Locality of Ngoundiane, Thiès region, Senegal) is presented. The grain size studied is 25/50 mm as for any material studied for use as railway ballast. Experimental work presented consists of the characterization of the shape of an aggregate using the NF P 18-301 standard. The test consists of comparing the volume of the aggregate to that of an equivalent sphere with the largest diameter of the aggregate, by calculating the average volume coefficient. With a Representative Elementary Volume (REV) of 6 aggregates, the volume coefficient “Cv” fluctuates between 0.27 and 0.49 with an average volume coefficient of 0.39 which is well above 0.15. The grains studied are polyhedral and therefore have a high mechanical resistance.