Since the early 1970s Ontario Ministry of Transportation (MTO) aggregate specifications have allowed the use of reclaimed materials as a component of unbound aggregate base. From an engineering perspective, reclaimed materials must meet the same requirements as natural aggregates. Specifications based on laboratory testing have been developed to allow the use of recycled materials in order to promote conservation of natural resources. Aggregates in road base/subbase may include up to 50 percent reclaimed asphalt pavement when used in conjunction with full depth reclamation (FDR). Samples of granular base material were collected from various FDR projects around the province and tested in response to reports that several recently constructed pavements using full depth reclamation have been experiencing premature cracking problems. Samples were subjected to a series of laboratory tests. Test results indicate a clear correlation between the strength and the percentage of asphalt coated particles present in the blend. The results also indicated that samples with the highest percentages of fines (material passing the 75micrometre sieve) also have the lowest coefficients of permeability. The results from these lab tests provide a better understanding of the properties and long-term performance of reclaimed asphalt pavement incorporated into the granular base. For the covering abstract of this conference see ITRD number E216597.
Abstract