Cold-Mix Asphalt Controlled by Ultra-Sound (CMACUS): Novel methodology for in-situ characterisation and improvement of interactions between bitumen emulsions and aggregate minerals

The use of cold mix asphalt compared to standard hot mix asphalt results in a lower energy consumption and CO2 emission, options for intermediate storage of a cold asphalt mix, low investment costs in production equipment and improved environmental conditions for the working force. To be able to apply this technology as high-performance asphalt the use of harder bitumen as a binder is necessary.

However, this leads to problems with curing of the bitumen emulsion.

The chemical processes controlling the curing are poorly understood and that is still a key research question to be properly addressed.In this project we will identify and map parameters that influence breaking, coalescence and structure build up in relation to the mineralogy and the surface characteristics of the aggregate fraction in cold mix asphalt during its production and laying (mixing, compaction and curing).

We developed dynamic (NMR relaxation and diffusion) and solid-state NMR methods for studies of interactions between bitumen emulsions and different minerals.

To better control and accelerate the process we will develop and evaluate ultrasound based methods for homogenisation of emulsions and to accelerate breaking by ultrasound ironing.

We also aim to develop test methods and guidelines for choosing raw materials suitable in the design of high performance cold mix asphalt.

This project is supported by industrial partners: Nynas AB (producer of bitumen emulsions) and a road paving company PEAB Asphalt.