Technology Roadmap Low-Carbon Transition in the Cement Industry

Figure 12: Global cement production and clinker to cement ratio in the 2DS
Sources: 
Base year data from CSI (2017),
Global Cement Database on CO
2
 and Energy Information
, 
www.wbcsdcement.org/GNR
; SNIC 
(forthcoming), 
Low-Carbon Technology for the Brazilian Cement Industry
; 
data submitted via personal communication by Sinoma Research 
Institute and China Cement Association (2016-17); CII, WBCSD and IEA (forthcoming), 
Status Update Project from 2013 Low-Carbon Technology for 
the Indian Cement Industry
.
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0
1 000
2 000
3 000
4 000
5 000
6 000
2014
2030 - 2DS 2040 - 2DS 2050 - 2DS 2030 - 2DS 2040 - 2DS 2050 - 2DS
Low-variability case
High-variability case
C
li
n
k
e
r
to
ce
m
e
n
t
ra
ti
o
C
e
m
e
n
t
p
ro
d
u
ct
io
n
(M
t/
y
r)
Other cement
constituents
Clinker
Clinker to
cement ratio
currently represent 25-30% of the global cement 
production, and that the share will increase by up to 
48% by 2050 in the 2DS.
Thermal treatment can enhance the reactive 
properties of natural pozzolanic materials. This 
entails a thermal energy penalty reported as up 
to 0.15 GJ/t cement compared to a reference plant 
thermal energy performance of 2.64 GJ/t cement 
(ECRA and CSI, 2017). Such is the case of calcined 
clay, a result of drying, crushing and calcining clay. 
Calcined clay has been used in cement production 
for a long time (bridge construction applications 
were reported as early as 1932 in San Francisco), 
with Brazil systematically producing about 2 million 
tonnes (Mt) calcined clay per year since the 1970s 
(UNEP, 2016). Early compressive strength of cement 
decreases with greater portions of calcined clay 
used due to the slower reaction kinetics of this 
cement constituent compared to clinker (ECRA 
and CSI, 2017). However, recent developments 
benefit from optimised combinations of calcined 
clay and ground limestone as cement constituents, 
potentially enabling up to 50% clinker displacement 
without affecting cement properties (UNEP, 2016). 

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