Earthquake-resistant homes of future could use this material as building blocks

Buildings in the future could be built using an unconventional material to help them face seismic activities better. This material could be thermocol, as per researchers at IIT Roorkee.

Using thermocol, or Expanded Polystyrene (EPS), as a composite material in core of reinforced concrete sandwich could make buildings earthquake resistant, effective up to four stories. It could also provide better thermal insulation as well as save energy required to develop construction materials.

The IIT Roorkee researchers tested a full-scale building and a number of wall elements constructed with thermocol sandwiched between two layers of concrete at the National Seismic Test Facility (NSTF) of the college's Department of Earthquake Engineering.

They evaluated the behaviour of the constructions under lateral forces, as earthquake causes a force predominantly in lateral direction. The investigation was supplemented with detailed computer simulation of a realistic 4-storey building.

Professor Yogendra Singh, who was supervising the research, stated that a four-storey building constructed with this technique is capable of resisting earthquake forces even seismic zone V of the country, which includes the most vulnerable regions, without any additional structural support.

This ability to resist earthquake forces has been attributed to the fact that the thermocol layer is sandwiched between two layers of concrete and reinforced with welded wire mesh.

The researchers said that the forces that lead to collapse of a building during earthquakes arises due to the inertia effect and hence depends on the mass of the building. Thermocol resists earthquakes by reducing the mass of the building, they added.

In this technique, the factory-made thermocol core and wire mesh reinforcement are used to create the building skeleton. Then concrete is sprayed on the skeleton core. Since this technique does not require any shuttering, the structure can be constructed very quickly.

Using thermocol in concrete walls in a building comes with the added benefit of thermal insulation. The core provides the necessary insulation against the heat transfer between building interior and exterior environment. This can help in keeping the building interiors cool in hot environments and warm during cold conditions. Different parts of India suffer a large variation of temperature during the course of a year, and thermal comfort is a crucial consideration in these areas along with structural safety.

This technique can also save construction material and energy, reducing the carbon footprint in the process. As the thermocol core replaces a large portion of concrete used in the building, it reduces the burden on natural resources and energy required to produce the material.