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Realistic Ways to Drastically Reduce the CO2 Emission of ...
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Realistic Ways to Drastically Reduce the CO 2 Emission of Cement and Concrete Farshad Rajabipour Department of Civil and Environmental Engineering Concrete is the #1 human-made material Annual world production: ~33 billion tons = 4.4 tons/person/year 1cm (Ashby 2013) Cement CO 2 emissions = 2.3 GT/yr (~6% of total anthropogenic CO 2 emissions) CaCO ଷ ୌୟ୲ CaO CO ଶ Limestone, clay 1450 o C Source: PCA • Cement chemistry uses most abundant elements on earth • New cement plants operate near thermodynamic efficiency Only scalable, impactful, and rapidly implementable solution to curb CO 2 emissions: Use less Portland cement 1. Replace cement with supplementary cementitious materials (SCM) 0 2 4 6 8 10 12 14 16 Silica fume Waste glass Biomass ashes Natural… Slag Fly ash Portland cement Limestone Calcined clay GT/yr LC 3 reduces CO 2 emissions of cement by up to 30% → ~85GT CO 2 reduction over 30 years 0 1000 2000 3000 4000 5000 6000 0 10 20 30 Compressive strength (psi) Age (day) Control LC3 SC3 ~ 30% carbon < ~5% carbon 2. Improve (double) the service life of concrete structures (100+ years) ASR damage Corrosion Asset Management New NY Bridge Conclusions and Acknowledgements Only realistic way of drastically reducing the CO 2 emission of concrete is to reduce the use of Portland cement: • Replace 50% of cement with SCMs • Double the service life of concrete structures
Transcript of Realistic Ways to Drastically Reduce the CO2 Emission of ...
Realistic Ways to Drastically Reduce the CO2 Emission of Cement and Concrete
Farshad Rajabipour
Department of Civil and Environmental Engineering
Concrete is the #1 human-made materialAnnual world production:
~33 billion tons = 4.4 tons/person/year
1cm
(Ashby 2013)
Cement CO2 emissions = 2.3 GT/yr(~6% of total anthropogenic CO2 emissions)
CaCO CaO CO
Limestone, clay
1450oC
Source: PCA
• Cement chemistry uses most abundant elements on earth
• New cement plants operatenear thermodynamic efficiency
Only scalable, impactful, and rapidly implementable solution to curb CO2 emissions: Use less Portland cement
1. Replace cement with supplementary cementitious materials (SCM)
0 2 4 6 8 10 12 14 16
Silica fumeWaste glass
Biomass ashesNatural…
SlagFly ash
Portland cementLimestone
Calcined clay
GT/yr
LC3 reduces CO2 emissions of cement by up to 30% → ~85GT CO2 reduction over 30 years
0
1000
2000
3000
4000
5000
6000
0 10 20 30
Com
pres
sive
stre
ngth
(psi
)
Age (day)
Control LC3 SC3~ 30% carbon
< ~5% carbon
2. Improve (double) the service life of concrete structures (100+ years)
ASR damage Corrosion
Asset Management
New NY Bridge
Conclusions and AcknowledgementsOnly realistic way of drastically reducing the CO2 emission of concrete is to reduce the use of Portland cement:
• Replace 50% of cement with SCMs• Double the service life of concrete structures
