Exploring Innovative Road Construction Technologies and Methods
The bituminous mix design method based on Marshall method is common in India, though it may not be suitable for heavy traffic roads, unless they undergo performance tests such as rutting and cracking. The world, however, has moved to the Superpave mix design method to address issues faced in the Marshall method, as the former can better simulate field compaction of the mix. As a trial, highway agencies should implement this technology in a few road stretches in order to compare its performance with mixes designed using the Marshall method.
One of the causes of road failure is the premature rutting in bituminous roads. There is therefore an interest among highway agencies to develop simple performance tools to assess the shear strength and rutting performance of mixes. Though there are many methods and equipment that can be used, they will require expensive instruments, skilled manpower, and time for processing the test results. Plus, they cannot be used during the production and construction phases as time is critical. The SPTs can be helpful for the industry, and the present edition gives direction on some performance tools.
In heavy traffic conditions, a gap graded aggregate mix such as the stone matrix asphalt (SMA) can prove to be beneficial. However, some recent failures of SMA have triggered panic in the highway agencies. SMA is a delicate mix that requires a good selection of aggregates, a proper mix design, and an efficient construction plan.
Considering sustainability targets, this issue of NBM&CW brings forth information on cold recycling, use of reclaimed asphalt pavement, and full depth recycling. Cold recycling with emulsion and foam-based additives is popular the world over. Cold recycling can be classified as in-situ or in-plant recycling. Adopting this technology on a larger scale can be beneficial in the long run.
Another innovative use of RAP is in roller compacted concrete (RCC), pavements an area which is emerging fast. Stabilization of aggregates / existing pavement materials can provide a stronger base to the pavement, which can optimize the thickness, reduce material usage, and prove to be resistant to water damage. Cement stabilization is quite common, and various additives are available in the market today that can be used for stabilizing or for recycling.
Articles in this issue of NBM&CW cover a wide range of topics – all of which will provide useful information to highway practitioners, consultants, and to research and construction agencies. The contributors of the articles are much appreciated for their deep subject knowledge and lucid presentation of the modern-day materials and technologies involved in road construction.
Guest Editor
Prof (Dr) Dharamveer Singh
Department of Civil Engineering, IIT Bombay
NBM&CW - JUNE 2024
