Testing of oil shale ash for use in road construction

In the second stage of OSAMAT, which started in July, analysis will be carried out to determine the most efficient way to turn oil shale ash into a material that can be used for road construction. The project, brought to life with support from the LIFE+ programme of the European Union, involves cooperation between Eesti Energia, the Estonian Road Administration, Nordecon and Ramboll.

The second stage of OSAMAT will explore ways in which oil shale ash can be used for the mass-stabilization of peat and other unstable ground materials. “When building embankments for railroads and motorways, unstable ground materials are usually removed and replaced with stable materials. An alternative solution is to mass-stabilize the earth with cement. Our project will attempt to mass-stabilize peat with oil shale ash. Binding agents in the ash will harden and stabilize the peat enough that road embankments can be built on it,” explains Tõnis Meriste, Environmental Development Manager at Eesti Energia and one of the leaders of the project.

Replacing some or all of the cement with oil shale ash in the mass-stabilization process makes it possible to curb the costs and widens the possibilities for reusing the ash. In the current stage of the project, different types of oil shale ash, and mixtures of ash and cement, are being used in mass-stabilization experiments on the section of road between Simuna and Vaiatu. The peat layer will be stabilized up to the depth of 3.3 metres and it will serve as the base onto which the road base and pavement will be constructed.

“A pilot section of 10,846 m3 of peat is going to be stabilized. Each 100-metre section will be constructed with different types of ash and various mixtures of ash and cement. On the pilot section, cyclone ash, pulverized combustion ash, and fluidized bed boiler ash will be used,” stated Arina Koroljoval, project leader of the Ash Sale Service of Narva Power Plants.

After the construction works are finished, the road sections that were treated with ash will be examined over the course of the next few years to gather information on how the sections that were stabilized with ash hold up. According to the current plan, the test sections built in this project will be monitored at least until the year 2016.

OSMAT’s first stage began in 2011 and involved experiments using oil shale ash for building road embankments. Ash was used as a stabilizing layer beneath the asphalt for the section of road between Narva and Mustjõe. Works conducted in the first two years of OSMAT are currently being evaluated and the resulting conclusions will be drawn in the next two years. Final conclusions on the possibilities of using oil shale ash in road construction will be drawn when the project is finished.

Моnika Kopti
Eesti Energia
GSM 521 2602
[email protected]