Alkali-Activated Cement for Equitable Slum Improvement in Mumbai, India - A Low-CO2, Low-Cost, and Equitable Alternative

In Mumbai, India, 3,000 slum pockets, often characterized by overcrowding and poverty, occupy 16% of land area and are home to over 50% the city's population of 12 million. Demonstrating that technology is central to sustainable development in general, and that of developing countries in particular, the Indian draft National Slum Policy calls for "...access to better technology and materials at cheaper prices." In response to the need for more sustainable building materials for slum improvement, a alkali-activated cements (AACs) were designed and developed over 6 months at the Indian Institute of Technology (IIT), Bombay. The needs of all stakeholders, including and especially those of slum dwellers, drove the design specifications and the proposal for implementation. Statistical Design of Experiment was used to rapidly develop formulae that pass each of the three grades of Indian Standard cement: 33, 43, and 53 MPa at 28 days. Cost savings were as high as 44%, yielding a savings on concrete of 7% and on a typical slum improvement project of 3-5%. CO2 and energy reduction was as high as 92%, significant because OPC is responsible for 5% of anthropogenic CO2. The use of AACs could benefit all stakeholders-contractors/builders, government bodies and politicians, the public, and slum dwellers - but current interests of those in power would limit the benefits directly enjoyed by slum dwellers. Because the materials developed are not patentable, an open source approach is the most promising.