The main Rural Road Gravel Assessment Programme (RRGAP) investigations, carried out by Intech-TRL at 766 road sites in Vietnam, found serious constraints to the use of gravel in most of the studied 16 programme provinces due to factors relating to material quality, material availability, climate, terrain, drainage provision and maintenance. Overall gravel loss figures indicate that around 58% of the surveyed sites are suffering unsustainable deterioration, while 28% are losing material at twice the sustainable rate. From the RRGAP investigations, and consideration of other complementary research and knowledge of the performance of gravel roads elsewhere, guidelines are proposed for the restriction and use of gravel as a rural road surfacing in the range of conditions experienced in Vietnam.
Intech Associates-TRL, UK, 105 pp.
SEACAP 4. Rural Road Gravel Assessment Programme. Final report.