Reuse of Solid Waste from the Clearing of Road Basins and Ditches in Civil Engineering: Environmental Characterization, Ways of Treatment and Their Efficiency - Highway and Urban Environment - page 176

Fig. 1 Experimental device of water loss

Sediments

Geotextil

slope

Presentation of the Water Loss Experimental Device

To appreciate the dryness evolution by open air spreading, the device presented in
Fig. 1 has been realized. It musts be noted that these tests were carried out inside,
and consequently sheltered from climatic hazards. Weighing has been carried out
with a measure uncertainty in the gram order. Each previously tared (box) weight
has been measured until stabilization.
First values may admit some distortions. Indeed this matter put for drying has
not the same dryness as the one within the basin. This link with the first measure is
not inconvenient facing the experiment objective, which is to determine the time
from which dryness is stabilized as well as the final dryness value. A first experi-
ment has been carried out with settling pond sediments. Two tests have been led
with 6.5 and 4.5 cm sediments thickness, respectively, at the beginning of the
experiment. Weight evolution was regularly followed-up. After 3 weeks a sample
was taken and put in a drying oven (150°C during 14 h). Dry soil sample mass was
determined, and by knowing sample weight during the course of time, it is possible
to deduce the moisture evolution.
To grasp sediment height influence on moisture evolution, other tests have been
carried out from B4-B6 basins located on Lyon's East RingRoad. Sediment was put
within tubes of variable diameter and height. A test in box similar to the first series
was set up as well. The adopted device is presented in Fig. 4 .
A drainage and water recovery device was also set up. At last, to prove that a
relative uniformity between sediments exists, B4-B6 and B17 sediments draining
has been compared for the same sediment height (5.5 cm). Sediments of these two
basins have rather different grain sizes, B17 being globally finer than B4-B6.

Result and Discussion

Sediment Environmental and Geotechnic Characterization

Ditches : The only studied variable concerning ditches is traffic. It emerges from the
first results that sediments from ditching cleaning out do not contain pollutions signifi-
cant in metal trace elements (nickel, chrome, cadmium). Concerning hydrocarbons,
zinc, copper, and lead, an increasing correlation between hydrocarbon content and
traffic supported by the road axis, could be observed (Table 1 ).