4.9.2 Geotextiles
Geotextiles may be used to reinforce sprayed seals for improved waterproofing over cracked or weak pavements. Geotextiles Reinforced Seals (Austroads 2005b) contains detailed information on these and other uses of geotextiles and the range of materials available.
The material preferred for reinforcement of sprayed seals is a non-woven needle punched polyester geotextile. The standard geotextile grade has a mass of 130–140 g/m2 with a heavier grade (175–200 g/m2) material adopted for severely cracked, heavily trafficked pavements where additional waterproofing is needed.
This type of material has been used in sprayed seals over cracked bituminous wearing courses, cement stabilised bases with shrinkage cracks, and on lightly trafficked roads with basecourses made of heavy clays with plasticity indices of 30 to 35. Table 6.6 presents the properties required of a geotextile for use in sprayed sealing.