The technical department of COMSA is leading the European I+D Life+ Gain for the use of steel waste, known as black slag, in the processes of construction and maintenance of railway lines. The black slag will be used for the sub-grade and sub-ballast foundation layers. This is a pioneering project in that it is the first time in Europe that this type of waste will be applied in the field of railway lines. To date it has mainly been used in the construction of roads.
Black slag, a type of steel from the electric arc furnaces used in the steel industry, is abundant in Europe. According to figures from EuroSlag, the European Association of Metallurgical Slag Producers and Processers, 2011 alone saw the generation of between 8.6 and 14.3 million tonnes of this waste. This project, which is currently underway, seeks to provide an environmentally sustainable solution through the valorisation of this abundant industrial waste, whilst also providing a qualitative enhancement over conventionally built railway lines. The use of black slag will enable a reduction in the quantity of natural aggregates used for this type of construction, a reduction in the volume of black slag sent to landfill, a reduction in construction costs and an improvement in the mechanical behaviour of railway tracks.
Research undertaken in previous R&D projects, such as ASICAP (Metallurgical aggregates in sub-ballast and sub-grade layers of railway platforms), also led by COMSA, shows that recycled aggregates have better mechanical properties than conventional aggregates, particularly in terms of durability and resistance to wear. In this respect, the Gain project consortium will undertake a pilot test in the coming months, consisting of the renovation of 100 metres of the Castellbisbal – Mollet / Sant Fost de Adif line using black slag, in order to assess its behaviour.
The European I+D Gain project is led by COMSA and has a budget of €1.3 million. It is envisaged that commercialisation of the project results will commence at the end of 2016.