Technology Roadmap Low-Carbon Transition in the Cement Industry

Technology Roadmap
Low-Carbon Transition in the Cement Industry
Recent blended cement developments have shown 
that up to 50% clinker displacement is possible 
through optimised combinations of calcined clay 
and ground limestone as cement constituents 
without affecting cement properties (UNEP, 
2016). This demonstrates interesting prospects for 
reducing the clinker to cement ratio as a carbon 
mitigation strategy, as it would rely on widely 
available resources such as raw clay, rather than on 
other clinker substitutes (e.g. GGBFS and fly ash), 
which are foreseen to have significantly reduced 
availability in the 2DS.
Alternative cement binding materials that rely 
on different raw material mixes or different raw 
materials compared to PC clinker are commercial 
or are being tested and developed by the cement 
industry to mitigate the environmental impact of 
process CO
2
emissions.
Commercially available 
alternative binding
cement materials
z
Belite clinker
contains no or little alite, and 
between 40% and 90% belite,
44
leading to about 
a 6% reduction of the process CO
2
intensity 
of clinker (Gartner and Sui, 2017). This type of 
clinker also benefits from a reduced burning 
44. A specific commercial example of belite clinker would be 
more than 40% belite and less than 35% alite according to the 
Chinese standard GB200-2003 for low-heat PC (Gartner and 
Sui, 2017).
temperature (1 350°C) compared to PC clinker, 
thereby reducing the fuel needed for calcination. 
Less than 10% thermal energy savings have 
been reported. The greater hardness of belite 
increases electricity use for grinding by about 
5% compared to PC (Gartner and Sui, 2017). 
Belite cements are produced at even lower 
temperatures (600-900°C), and have been 
produced at the laboratory scale (ECRA and 
CSI, 2017). Current market deployment of belite 
cements is limited (and confined to a small 
number of countries) due to their much lower 
early-strength characteristics. Their low heat 
of hydration
45
means that belite cements have 
mainly been used in massive concrete dams 
and foundations (UNEP, 2016). China has been 
producing belite cements over the past 15 years, 
with the first successful application for dam 
construction in the third phase (2003-09) of the 
Three Gorges Hydropower Project (Gartner and 
Sui, 2017). In 2014, China produced about 1 Mt 
of belite cement; Japan is also using high-belite 
cements for mass concrete and high-strength 
concrete (Gartner and Sui, 2017).
z
Calcium sulphoaluminate (CSA) clinker 
contains ye’elimite as the main constituent, which 
directly reduces released process CO
2
emissions. 
For instance, a commercial CSA clinker yields a 
44% reduction in process CO
2
intensity of clinker 
45. Heat of hydration refers to the heat released as a result of the 
exothermic reaction between cement and water. It needs to 
be limited in mass concrete applications to reduce the risk of 
thermal cracking.