Study of the impact of the compaction and curing temperature on the behavior of cold bituminous recycled materials

In most countries, there is a low temperature limit to lay down hot asphalt mixes because if it is too cold, it becomes impossible to get proper compaction. For cold recycled bituminous mixture (CRM), there is little information on the effect of the low temperature on their behavior. The goal of this study is to evaluate, in laboratory, the impact of the compaction and curing temperature on the behavior of CRM. To do so, CRM containing 50% reclaimed asphalt pavement (RAP) and 50% natural aggregates treated with foamed asphalt or bituminous emulsion were mixed and cured at different temperature between 0 °C and 23 °C for up to 10 days before being tested in indirect tension. The results show that for all mixes, a cure at lower temperature means lower tensile strength, but the decrease is more noticeable for emulsion treated materials than for foamed treated mixes. The trend is not as obvious for Marshall stability results. A second cure at ambient temperature was also done, and the analysis of the results showed that the decrease in mechanical performance remains important even after a second cure at higher temperature for all mixes treated with bituminous emulsion, but there is some mechanical gain for mixes treated with foamed asphalt.