The growing population in the modern world has resulted in an increase in waste generation and stockpiles. There have been increasing concerns on how to sustainably reuse wastes in civil and geotechnical engineering applications. Two major municipal waste streams are plastic wastes and recycled concrete aggregate (RCA) generated by demolition activities. A potential application for growing stockpiles of plastic and RCA waste is in the construction of roads because pavement base and subbases typically demand significant quantities of construction materials. In this research, RCA was blended with low-density polyethylene (LDPE) and high-density polyethylene (HDPE) plastics. A range of geotechnical tests such as California bearing ratio (CBR), unconfined compressive strength (UCS), and repeated load triaxial (RLT) tests were conducted on RCA–HDPE and RCA–LDPE blends. Comparison of CBR, UCS, and RLT results with those of typical quarry materials indicated that RCA–HDPE and RCA–LDPE can be used sustain...

Laboratory testing methods are constantly being developed to simulate true field conditions in controlled laboratory environment. The aim of laboratory testing methods is to reproduce specimens which accurately replicate field performance in terms of mechanical behaviour of pavement materials under applied loads. Compaction is the most common soil stabilisation technique in ground improvement and pavement construction works. Among the available laboratory compaction methods, the impact method followed by the static method are the most commonly used procedures. Since the nature and approach of these two compaction methods are fundamentally different, an investigation on the effect of using these techniques on the mechanical performance of pavement materials prepared by each of these methods is essential, so as to better understand both these compaction methods. In this regard, two types of recycled construction and demolition (C&D) materials suitable for pavement applications, namely crushed brick (CB) and recycled concrete aggregate (RCA) were selected. Laboratory specimens were prepared using the above-mentioned procedures. Different aspects of geotechnical characteristics of the specimens, including aggregate breakage, changes in soil–water characteristics, stiffness, and resilient characteristics, were investigated. The outcomes of this research indicate that the influence of method of compaction must be considered when interpreting the laboratory test results for field design purposes.

The application of recycled aggregates in the asphalt industry has been investigated in recent decades. However, low percentages of these materials have practically been used in asphalt mixtures because of the limitations set by the relevant specifications due to their performance uncertainties. This research investigates the feasibility of increasing the percentage of recycled aggregates to 100% in hot mix asphalt (HMA). Recycled concrete aggregate (RCA), recycled glass (RG), and reclaimed asphalt pavement (RAP) were used to develop HMAs suitable for roads with light to medium traffic. First, potential mix designs were proposed using an innovative approach considering the industry’s needs. Next, the volumetric properties, tensile strength, moisture sensitivity and resilient modulus response of the mixtures under different temperature conditions were determined and compared. In general, the proposed recycled material HMA exhibited superior mechanical and resilient modulus performances, i.e., 45 to 145% increase in stiffness, and up to 99% higher in Marshall stability. Furthermore, higher tensile strength ratios of the recycled material mixtures indicated a greater resistance to water damage, and hence greater durability. The findings of this research provide evidence-based insights into the increased proportion of recycled materials in the construction of asphalt pavements, thereby promoting sustainable pavement construction materials.