Given the renewal of urban infrastructure and the increased costs of landfilling concrete rubble materials, opportunities exist to optimize the reclamation and recycling of portland cement concrete (PCC) and hot-mix asphalt concrete (HMAC) rubble through their innovative use in road rehabilitation. The primary objective of this study was to demonstrate the ability to reclaim, process, and recycle stockpiled concrete materials to provide improved structural mechanistic–climatic material properties and to meet or exceed the mechanical properties of conventional granular road materials. This research was based on advancements made in 2009 as part of the Green Streets Infrastructure Program in the city of Saskatoon, Saskatchewan, Canada. A second objective of this research was to pilot the field application of reclaimed and recycled HMAC and PCC rubble in typical urban road reconstruction applications. Recycled HMAC and PCC materials were used in the pilot reconstruction of a road that was exhibiting substructure moisture problems and structural failure. This study showed that recycled HMAC and PCC rubble materials could be processed to achieve mechanistic laboratory properties that exceeded those of conventional granular-based materials. This study also demonstrated efficient constructability and high end-product structural asset value of a typical rehabilitated urban road structure test section in the city of Saskatoon by using recycled HMAC and PCC rubble. On the basis on these findings, the use of quality processed HMAC and PCC rubble materials for road reconstruction was found to be a technical and environmentally sustainable solution.

The purpose of this research was to determine how asphalt cement binder types influence the mechanical behaviour of hot mix asphalt concrete mixes. This research employed triaxial frequency sweep characterization of a typical City of Saskatoon Hot Mix Type A2 and a typical Saskatchewan Ministry of Highways and Infrastructure Hot Mix Type 70 across a range of triaxial load frequencies and stress states representative of Saskatchewan field state conditions. The asphaltic mixes were evaluated across four asphalt cement binder types typically employed by Saskatchewan road agencies. Based on the findings of this study, the mechanical behaviour of both asphalt mixes evaluated were found to be highly sensitive to load rate, stress state, as well as asphaltic binder type. It was concluded that load rate, field stress state, and asphalt binder type should be incorporated into the structural design of hot mix asphalt concrete pavements to ensure adequate mix performance, particularly when placed in severe field conditions.

This study was undertaken to evaluate the effect of soil type, moisture content, and the presence of frost on road substructure permittivity. Permittivity sensitivity of typical road soils was characterized in the laboratory to provide baseline dielectric constant values which were compared to field ground penetrating radar (GPR) survey results. Both laboratory devices, the complex dielectric network analyzer and the Adek Percometer, as well as the field GPR system were used in this study to measure the dielectric constant of soils. All three systems differentiated between coarse-grained and fine grained soils. In addition, at temperatures below freezing, all three systems identified an increase in water content in soils; however, when frozen, the sensitivity of dielectric constant across soil type and moisture content was significantly reduced. Based on the findings of this study, GPR technology has the ability to characterize in situ substructure soil type and moisture content of typical Saskatchewan road substructure soils. Given the influence of road soil type and moisture content on in-service road performance, this ability could provide road engineers with accurate estimates of in situ structural condition of road structures for preservation and rehabilitation planning and optimization purposes.

This study investigated the mechanistic climatic constitutive behaviour of granular materials from Saskatchewan, Texas, and Finland. This research employed triaxial frequency sweep testing to characterize various quality granular materials with and without cement modification. Cement stabilization showed a consistent improvement in the response of poor and well graded granular materials, relative to untreated granular materials in terms of both mechanical behavior and climatic durability. As a result, when cement stabilized, poorly graded (or dirty bases) with high fines and (or) fine sand content can be engineered to perform better in the field than well graded (or clean) bases. This research showed that climatic conditioning of laboratory samples significantly influences the mechanical behavior of both unstabilized and cement treated granular materials. Therefore, when characterizing granular base materials for structural design purposes, the mechanistic properties and the effect of climatic conditioning of granular materials representative of field state conditions are needed to provide accurate structural design purposes.

Full-depth reclamation and cement strengthening has been used successfully to dry and strengthen granular pavements. However, some thin pavements fail due to severe wetting-up of the subgrade, thus requiring additional substructure strengthening and (or) drainage systems. This research investigated the laboratory characterization and in situ field mechanical behaviour of full-depth reclaimed and cement-stabilized granular materials in conjunction with a woven geotextile and sand drainage system. This research showed that the integration of cement-stabilized reclaimed granular materials with a geotextile separation layer and sand drainage system significantly improved the mechanical primary response and climatic durability properties of the reclaimed road structure. The cement-stabilized and geotextile separation–drainage system improved the structural asset management test results from a completely failed road structure to primary plus load-carrying capacity. This research also demonstrated an improved correlation between the mechanistic material constitutive properties of the stabilized aggregate to the end-product field structural assessment relative to conventional California bearing ratio and unconfined compressive strength test results.