Sustainable production of lightweight vitreous aggregates for the construction industry

CSIC scientists have developed a process to obtain lightweight vitreous aggregates from waste glass and industrial waste. Its implementation is a clear commitment to a circular economy. The method has been patented and is available for industrial implementation.

Lightweight aggregates obtained with this method have similar density and strength values to those currently on the market.Lightweight aggregates are widely used in construction to make concrete, lightweight precast concrete and insulating barriers. Unfortunately, the process of extracting natural aggregates affects the environment, as it transforms the landscape and causes the degradation of natural resources. In addition, there is a high energy cost due to processing at very high temperatures.

Scientists at the CSIC's Eduardo Torroja Institute of Construction Sciences have developed a process to obtain lightweight vitreous aggregates from waste. It is based on the use of glass cullet as a base and, on the other hand, uses different carbonated waste as a foaming agent, such as those from the food industry (eggshell or bivalve shells) or from the mining industry (those generated in the magnesite production cycle).

By means of a thermal shock process, light aggregates are obtained with densities between 0.55 and 0.80 grams per cubic centimetre and strength values between 0.65 and 1.10 Mega Pascals, which makes them comparable to commercial light aggregates and, therefore, suitable for various applications in construction.

The process is simple and easily scalable to industrial scale. During the thermal expansion treatment, it is achieved a structure with the right porosity in just few minutes. The result is materials with properties similar to those of commercial lightweight aggregates, but with less environmental impact.

The materials obtained can be used as thermal and acoustic insulators; water-repellent material; foundation materials for lightweight construction, slabs for industrial buildings, road construction, lateral load reduction in basement walls and bridge piers; non-openable surfaces (urban and industrial roofs); landscaping (vertical walls and garden design), among others.

Contact:

Patricia Thomas Vielma
Deputy Vice-Presidency
for Knowledge Transfer - CSIC
Tel.: +34 91 568 18 25
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