Indian researchers have developed a technology to produce energy-efficient walling materials using construction and demolition waste (CDW) and alkali-activated binders. Called ‘Low-C Bricks,’ these do not need high-temperature firing, and avoid the use of high-energy materials such as Portland cement. The technology will also solve the disposal problems connected with construction and demolition waste mitigation, a Science and Technology Ministry statement said on Thursday.
Scientists at the Indian Institute of Science (IISc) developed the technology for producing alkali-activated bricks/blocks by utilising fly ash and furnace slag. The team of researchers developed low-embodied carbon bricks from building waste through the alkali activation process.
“After ascertaining the physio-chemical and compaction characteristics of the CDW, the optimum mix ratios of the materials were
obtained, and then the production process was evolved to produce ‘Low-C Bricks.’ Based on the optimum binder proportions, the compressed bricks were manufactured. The bricks were examined for engineering characteristics," the release stated.
This development becomes important in view of the fact that conventionally, building envelopes consist of masonry walls built with burnt clay bricks, concrete blocks, hollow clay blocks, fly ash bricks, lightweight blocks, and so on and these envelopes spend energy during their production, thus incurring carbon emission and consume mined raw material resources which lead to unsustainable constructions.
The masonry units are manufactured either through the process of firing or using high-energy/embodied carbon binders for example Portland cement. The annual consumption of bricks and blocks in India is about 900 million tonnes. Besides, the construction industry generates vast amounts (70-100 million tonnes per annum) of waste material.
In order to promote sustainable construction, two critical issues require to be addressed while manufacturing the masonry units - conserving mined raw material resources and emission reduction. The new technology will assist beat these two problems, the statement said.
The major beneficiary of this development undertaken by IISc Bangalore with funding from the Department of Science and Technology, is the construction industry in general, and the building segment in particular.
“A start-up has been registered which will be functional within 6-9 months to manufacture low-C bricks and blocks with IISc technical help. The start-up unit will function as a technology dissemination unit through training, capacity building, and providing technical know-how for establishing such commercial units across India," stated Professor B.V. Venkatarama Reddy from IISc Bengaluru.