City lab develops tech to build cooler, quake-resistant structures

Chennai: City researchers developed two technologies for constructing climate- and seismic-resistant structures in remote and mountainous regions, using eco-friendly precast blocks and panels. A research team at the CSIR–Structural Engineering Research Centre (SERC) built a 500 sqft. prototype structure using the two patented technologies, which was recently inaugurated at their campus in Taramani.

Researchers said one of the technologies involves the use of eco-friendly interlocking masonry blocks (EIMB) made from industrial wastes like calcium carbide sludge — a byproduct of acetylene gas production — and fly ash generated from burning coal in power plants. Their use helps reduce pollution that would otherwise result from the large quantities in which these byproducts are produced. Only 10% cement was used to facilitate demoulding. "The structural walls built using EIMB improve seismic resilience through mechanical interlocking, made possible by the novel geometric configurations and bond pattern," the researchers said.

While two rooms in the building had walls constructed with EIMB, two more rooms were built using thermally efficient lightweight blocks (TELB) made of ferrocement sheets with a layer of expanded polystyrene or EPS (thermocol). These blocks are lightweight, and the use of EPS reduces thermal conductivity, making the rooms at least 5°C cooler than outside temperatures during summer and warmer during winter. They are also seismic-resilient due to their significantly lower seismic mass or low inertia. SERC researchers said the prototype building is fitted with a thermal monitoring system.

Researchers used another patented technology called Steel EPS Concrete Re-organised Building Technology for roof of the structure. The technology uses sandwiched lightweight panels that are lighter by 40% and reduce construction cost by 20%. These panels, which can be installed quickly, are seismic-resilient, corrosion-resistant, have high thermal insulation, offer high ductility, and are easy to maintain."For the next year, we will be measuring both temperature and humidity levels in different weather conditions," said N Anandavalli, director, CSIR-SERC.