LC3 is a new type of cement that is based on a blend of limestone and calcined clay. Limestone Calcined Clay Cement (LC3) is a low-carbon cement and it can reduce CO2 emissions by up to 30%, is made using limestone and low-grade kaolin clays are used for the production of LC3 and are abundantly available in many parts of the world, is cost effective and does not require capital intensive modifications to existing cement plants.
The main components of LC3 are clinker, calcined clay, limestone, and gypsum. Its manufacturing process involves synergetic hydration. Adding large amounts of calcined clay and ground limestone to concrete mixtures, the aluminates from the clay interact with the calcium carbonates from the limestone. The additional alumina in the metakaolin reacts with the ground limestone, leading to a less porous material than other cements and providing equal strength with higher levels of clinker substitution.
For every 20 tonnes of man-made CO2 that enter the atmosphere, one comes from the kilns of cement factories. Emissions in cement production are threefold:
Reducing the amount of clinker in cement, reduces the amount of CO2 in the atmosphere. Now, the amount of clinker is reduced by half in LC3.
LC3 allows growth without abstinence due to resources and CO2 efficiency
With current clinker production facilities, production capacity for cement can be increased twofold without increasing total CO2 emissions. Quarry life can then be considerably extended and costly Carbon capture and storage technologies for emission abatement can be avoided. Emissions of LC3 are estimated to be 20-30% lower than Portland cement because:
Existing equipment can be used
LC3 can be produced with existing manufacturing equipment, leading to only marginally increased investments for calcining equipment.
Lower cost of production
Reduced clinker content, decreased fuel consumption for calcination compared to clinker plus the fact that limestone does not need to be heated should contribute to lower production costs. Lower production costs are one of the main drivers for technology uptake.
A well-known technology
Clinker–Limestone systems and Clinker–Calcined Clay systems are well established. In effect, LC3 is optimises the synergy between two already known chemical systems. This leads to a higher degree of confidence that the materials will be durable since the chemical nature of the hydrates and pore structure are similar to other blended cements which have proven durable.
Using low-grade clay and limestone does not require opening new quarries nor deplete agricultural soils.
Industrialisation brought comfort to our lives, but at the expense of environmental resources. To have access to a decent shelter is among the most basic rights, however it often requires the use of concrete, the most manufactured material by volume. The quantity of cement produced has increased dramatically because of the growing world population, economic development and rapid urbanisation.
The projected volume of cement production by 2050 is about 6 billion tons. In 2014 alone 4.2 billion tons of cement was produced globally and accounted for 2.7 Gt of CO2 emissions, approximately 7% of the total anthropogenic CO2 emissions worldwide, making cement the second largest carbon dioxide (CO2) contributor in industry after power plants. Emissions from cement production are mainly caused by the loss of chemical CO2 during the raw materials clinkerisation, and the transport.
Limestone Calcined Clay Cement is a low-carbon alternative to the standard Portland cement and it reduce CO2 emissions related to cement manufacturing of cement by reducing the amount of clinker, replacing it with limestone and calcined clays. Usage of LC3 helps in achieving the sustainable development goals.
AAKAAR aims at creating a platform to compete, learn and promote Civil Engineering amongst the education fraternity through Competitions, Events and ICES, IIT Bombay (research paper conference) and also to make a festival of all and for all the Civil Engineering students.