Embodied Energy and CO<sub>2</sub> Analyses of Mud-brick and Cement-block Houses

Abstract

In building projects, the extraction of vast quantities of materials is too common. The extraction of materials and the erection of buildings consume embodied energy and emit carbon dioxide (CO2) that impact negatively on the environment. Therefore it is necessary to consider embodied energy and CO2 amongst other factors in selecting building materials for use in building projects. In most developing countries, building environmental performance analysis has yet to gain interest from the construction community. However, with recent increase in sustainability awareness, both developed and developing nations have engaged in efforts to tackle this challenge. Embodied energy and CO2 are among the leading parameters in assessing environmental building performance. In Cameroon, studies about the assessment of embodied energy and CO2 of building projects are scarce. Hence, professionals find it difficult to make alternative choices for building materials to use in their different building projects. This study uses a detailed process analysis approach supported by two popular housing types in Cameroon (mud-brick and cement-block houses) to assess the embodied energy and CO2 impacts from building materials. The emerging Building Information Modelling (BIM) tool was used to validate the computational results of the process analysis method. The findings revealed the embodied energy and CO2 for the mud-brick houses are 137934.91 MJ (2007.8 MJ/m2) and 15665.56 Kg CO2 (228.03 Kg CO2/m2); the cement-block houses are 292326.81 MJ (3065.51 MJ/m2) and 37829.19 Kg CO2 (396.7 Kg CO2/m2) respectively. Thus, the cement-block house expends at least 1.5 times more embodied energy and emits at least 1.7 times more embodied CO2 than mud-brick house. Although these findings cannot be generalized, they nonetheless indicate the importance of considering embodied energy and CO2 in making alternative choices for use in different building projects.