Page 15 - CSEB Report

Study on Compressed Stabilized Earth Blocks

5. Carbon Emission and Energy Efficiency

During the production of CSEB bricks at MoWHS’s platform, Carbon Dioxide emission
analysis was conducted according to Environment Agency, UK taking the actual working
scenario as followed:

1. 0.5 tonne of soil transported from 10kms distance

2. 0.057 tonne of cement transported from 1km distance
3. 7 people at site permanently

The personnel motion dominated the carbon dioxide emission with 88 kg CO2e, followed by

cement (Portland) with 50 kg CO2e and lastly soil with 13 kg CO2e as shown in the
following graph. This indicate that soil does not contribute to CO2 emission, rather the 13kg
CO2e was contributed by transportation of soil from 10kms distance.

The 50kg CO2e was also contributed by using 57kgs of cement as stabilizer mix. The mix
ratio taken was quite high ( 1:6,1:8, 1:10) compare to normally practice world-wide which
is 1:19 [1]. This conclude that more cement mix lead to more carbon emission, thus usage of
cement stabilizer should be minimize as low as possible.

The CO2 emission of by workers motion dominated the graph shown in Figure 5, however,
upon analysis it is understood that the graph would change depending on the project size,
the mix ratio and the transportation distance. Thus, CO2 emission contributed by cement
increases with decreasing in mix ratio (eg. 1:10, 1:8, 1:6..) and vice versa.

Figure 5: Chart showing CO2 emission during manufacturing of bricks

Since, the soil is a natural raw material, it does not require intensive upfront processing, thus

the energy consumption during production is very low comparing to other bricks. According
to [10], CSEB bricks creates 22 kg CO2/tonne compare to that of concrete blocks (143 kg

CO2/tonne), and common fired bricks (200kg CO2/tonne) during the production. In
addition, CSEB consumed less than 10% of the input energy as used to manufacture similar

14 Engineering Adaptation and Risk Reduction Division (EARRD), DES, MOWHS