Assessment of two laboratory design methods for CIR mixtures with bitumen emulsion based on static and gyratory compaction

Abstract To expand the body of knowledge regarding cold in-place recycled mixtures, this study presents two different laboratory design methods. The main differences between the methods are the compaction procedures (static and gyratory) and the required strength tests (unconfined compressive strength and indirect tensile strength). Specimens were manufactured using both methods, with different contents of bitumen emulsion and added water. The effects of adding Portland cement and increasing the compaction energy were also investigated. The compliance with strength criteria was reviewed, and the optimal bitumen emulsion and water contents were identified. The requirements of the specification based on gyratory compaction proved to be excessively high. A reduction of the values is suggested, and further research is encouraged to allow new benchmarks to be set.