ABSTRACT
The increasing demand to reuse excavation materials, to use soil in place or materials with high fine contents in the construction of Mechanically Stabilized Earth structures leads to the extensive application of soil stabilization technics such as lime, cement or fly ash treatment.
Soil treatment is an economical solution to exploit poor in-situ materials that cannot be implemented in their natural state. The treatment improves, in short terms, the physical parameters of the soils allowing its workability. However, such treatments also modify the chemical parameters of soil such as alkalinity in durable manner. The pH will remain well above 10 for very long period even at low dosage. Most of the MSE structure reinforced with geosynthetic uses PET based products. It is well established that PET is only suited for soil having pH ranging from 4 to 9. In highly alkaline environment, the degradation mechanism is strongly accelerated particularly when mechanical stresses are applied on the material. Then using PET in treated backfill is a clear risk for a structure integrity.In this paper, we will propose an extensive review of treatment technics detailing the gradual transformation of the soil alkalinity with time, then we will provide technical data showing the performances of PET reinforcement materials when exposed to alkalinity in the conditions of reinforcement applications, finally we will propose alternative solution such as the use of PVA reinforcement material and present their performances.
