Construction experiences with volcanic unbound aggregates in road pavements

Abstract

This experimental research discusses the performance of crushed granular materials resulting from volcanic rocks employed in the construction of subgrades and continuous grading unbound aggregate road base courses. Some frequent doubts related to their suitability for the aforementioned use, to their observance of the technical specifications of different countries, and to the methodology and criteria to control field compaction and bearing capacity are intended to be clarified. For this purpose some experiences of several Atlantic islands (Azores, Canary Islands, Cape Verde, Iceland) are compiled and additional recommendations are contributed for volcanic aggregates as those of Canaries or Azores. The experimental results reveal that it is possible to reach a good load-carrying capacity with these granular materials, and also that conventional tests can be used. The in-situ study has allowed us to obtain the rate of compaction as a function of the Effective Modulus of the base course foundation.