The term reinforcing in road paving means the ability to distribute a concentrated load over larger area of the subgrade , thus avoiding local over- loading of the bearing capacity . A closer analysis of reinforcing function of geotextiles in road construction reveals the presence of two types of reinforcement, the membrane reinforcement and horizontal reinforcement.
In practice, both functions acts simultaneously to improve the load- bearing capacity of the structure.
- Membrane reinforcement
Membrane reinforcement is mobilized when the subgrade is deformed by rutting. As subgrade deforms under loading , the geotextile stretches like a hammock, as shown in figure (I-11) .The loading is thus distributed over a wider area , as a result of the vertical component of the tension developed in the geotextile. Rutting and resulting spread of the load by geotextile continues until an equilibrium is reached.
Thus , with geotextile’s membrane reinforcement , a road can be constructed on a subgrade with low load – bearing capacity. In areas , where the sub- soil has a strongly varying load- bearing capacity, the use of geotextiles can relieve stresses at weaker points and thus promote a more uniform deformation of the subgrade.