For the construction works & urbanisation, concrete is the main backbone of the modern society since last 3 decades, so the cement consumption (per capita cement consumption current status is 290 kg in India, below the global avg. value of 540 kg) is growing day by day, due to this concrete is the 2nd most consumed materials applicable for in all sectors, by man-made after the water in our earth. For these, the vast increasing the percentage of carbon footprints via. CO2 emissions from the large production of the concrete which also lead to temp. increasing into the environment & tends to climatic change, which lead to increase the GWP (Global warming potential). Clinker substitutions, application of SCMs, performance-based specifications, CCUS, re-circular economy & renewal energy integration are the most successful decarbonisation/low & zero carbon construction levers for all massive carbon emission countries, to control the global temp. rise not > 1.5-degree C.Apart from these, the negative effects of OPC/clinkers, we can replace it by the application of SCMs to driving the concrete decarbonisation or reduce around 20% (rough estimation) of total CO2 emissions according to Net Zero Carbon Roadmap for Cement & Concrete, as per GCCA. As per recent data, it has been observed that, total CO2 emission across the world, 08% contribution done by all types of concreting works, specially from the concrete production by OPC, like 1 MT of OPC Cement can produce equivalent to (including from production, transportation, and application for quantum of usages) 980 kg eq. of CO2 emissions, similarly 1 m3 concrete can produce around 600 kg of CO2 eq. Due to these, cement industry should change their course to reduce the CO2 emissions effects by application of reducing the percentage of clinker (main responsible to carbon footprints or CO2 emissions), replace by SCMs (supplementary cementitious materials) and make new types of cement/binder like PLC (Portland lime stone cement), LC3-50 (limestone calcined clay cement with 50% clinker), Composite cement etc (ternary blending with OPC/clinker along with Fly ash & GGBFS), which will acts as low carbon binders.
Sasanka Sekhar Dey (Fri,) studied this question.