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Maity S.,Technology and Action for Rural Advancement
RILEM Bookseries | Year: 2015

The current trends of production and consumption are unsustainable in terms of environmental emissions and resource use. With current trends of energy application, the emission and resource use will increase nearly two-fold by 2050, creating an increased stress on the global resource base. Thus the only option is to create and promote low carbon and resource efficient technologies without compromising on the cost of goods produced and financial viability. As per WBSCD, by 2010 the cement industry in India alone contributed to 7% of the total CO2 emissions of the country. Realizing this the Indian cement industry has embarked on an ambitious roadmap of reducing it by 50% within 2050. Despite this improvement, still the emissions will rise from current (2010) 137 MtCO2 to around 468 MtCO2 by 2050. The present initiative explores the role of a new type of developed low carbon cement in reducing CO2 emissions and natural resource use. The cement is based on a ternary blend of calcined clay-limestone-clinker. Building made out of this low carbon cement and its associated building materials indicates a preliminary saving of 0.46 kg CO2 per square meter and 1.55 kg wastes per square meter. Considering the fact that India has a current shortage of 1.2 billion square meter of rural and urban housing which is increasing by 10% per year, the potential of CO2 and resource saving from sustainable construction is quite high considering only the housing sector. © RILEM 2015. Source


Maity S.,Technology and Action for Rural Advancement
RILEM Bookseries | Year: 2015

The cement industry has long recognized that the cost of energy can be significant, varying between 25 and 35% of total direct costs. Consequently, the industry is continuously investigating and adopting more energy-efficient technologies to improve its profitability and competitiveness. In particular, plants have moved steadily away from less energy-efficient wet process kilns toward the more fuel-efficient dry process kilns. The industry has achieved additional energy efficiency gains by using pre heaters and pre calciners. These technologies have helped the industry reduce its energy consumption per tonne of cement by 30%. Since these processes has attained its maximum outreach, the present study focuses on role of blended cement in reducing energy consumption during the cement manufacturing process. This has been achieved primarily due to adaptation of significant steps which was not being practiced during the production of conventional cement. Firstly as the use of even inferior quality of limestone can be used, it will save huge amount fossil fuels, which otherwise had been used during transportation of superior quality of limestone from large distances. Additionally since the limestone will not undergo through clinkerization, it will save enormous amount of energy. It is also being found that this blended cement uses calcined clay at lower temperature, and hence will be able to save huge amount of energy. © RILEM 2015. Source


Maity S.,Technology and Action for Rural Advancement
RILEM Bookseries | Year: 2015

In order to reduce the Greenhouse Gas (GHG) emissions from the cement industry, the percentage of clinker in cement blends can be reduced by using various other materials, such as calcined clay, low grade (dolomitic/siliceous) limestone, which are often available at the cement manufacturing site itself. The present study focuses on direct or indirect impacts on CO2 emission by reducing the use of high temperature clinker by low grade limestone during the production of low carbon cement. Implementing raw material substitution is fairly simple technically and requires comparable capital investments but the application is subject to the availability of the substituting materials. They offer opportunities to significantly reduce CO2 emissions arising from cement production. The production of limestone calcined clay cement has strong positive environmental credentials. It has substantial potential of CO2 abatement which is mainly achieved due to conserving fast depleting cement grade limestone reserves, utilizing unused low grade limestone not suitable for conventional cement manufacturing and reducing energy consumption, leading to emission reductions during finished grinding (low grade limestone being softer to grind compared to clinker). © RILEM 2015. Source


Maity S.,Technology and Action for Rural Advancement | Bishnoi S.,Indian Institute of Technology Delhi | Kumar A.,Technology and Action for Rural Advancement
RILEM Bookseries | Year: 2015

A majority of the commercial cement production in India is based on substitution of clinker by pozzolanic materials in the form of fly ash from thermal power plants or blast furnace slag. The present study investigates the field application of a new type of ternary blend using limestone, calcined clay and clinker with small amount of gypsum. Four different blends were manufactured under pilot scale. Two different calcined china clay was used; one with a high kaolinite content and the other with a very low kaolinite content but high iron oxide phases giving a white and red colour to the respective blends. Two different limestone with varied quality was also used. Various types of alternate building materials were produced with these four blends for roofing, walling and flooring applications. Comparative study was undertaken with Ordinary Portland and Pozzolan Portland cement locally available. It was found that with a 30% clinker replacement by high kaolinite calcined china clay the building materials show a higher strength compared to those manufactured with normal available cement. Even the low kaolinite content clay show comparative quality with 30% replacement. No effect on productivity of the various types of building materials were observed. A two storied demonstration building has also been constructed entirely from the new blended cements. It was concluded that it is possible to replace 30% or even more clinker by calcined clays to produce acceptable quality building materials. © RILEM 2015. Source


Maity S.,Technology and Action for Rural Advancement | Bishnoi S.,Indian Institute of Technology Delhi
RILEM Bookseries | Year: 2015

Low carbon cement is a ternary blended Portland cement with clinker factor as low as 0. 40. It uses the synergetic hydration of clinker, calcined clay and crushed limestone to achieve comparable properties of commercial cements. One of the major components of low carbon cement is calcined china clay having a kaolinite content as low as 20%. The present report discusses the availability of required clays in two surveyed areas of Rajasthan and West Bengal. Characterization of clays have been performed through various techniques and their suitability established from thermo-gravimetric analysis supplemented by mineral and chemical composition. Medium grade china clay (40-60% kaolinite) is abundantly available in Rajasthan, whereas very high grade (60-80% kaolinite) is commercially available in West Bengal. It was difficult to get low grade china clay under commercial terms and conditions although it is dumped as wastes in and around mine areas. All the various grades of china clay were found to be suitable for use in low carbon cement by replacing clinker. © RILEM 2015. Source

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