Development of an environmental profile for globigerina limestone blocks and locally-manufactured hollow concrete blocks through the use of life cycle analysis

Abstract

Human actions and their effect on the environment have been an ever-increasing concern, both for scientists and the public at large. The construction industry is an important sector of the local economy, and a major player in the quality of our built environment; yet it also has its negative effects on the environment on a larger scale. This study set out to establish the environmental sustainability of two of the most commonly used building materials locally: Hollow Concrete Blocks (HCB) and Globigerina Limestone Blocks (GLB). Environmental standards are inexistent for either HCB and or GLB production. Moreover, the future of the local quarrying industry does not look bright, with a multitude of policies by the local authorities which discourage this industry from expanding further, mainly because of its almost irreversible impact on the landscape. Mineral reserves are also said to last for the next 30 years only. Through the use of life cycle analysis, the production processes of these two materials were analysed. It has been established that HCBs have a higher embodied energy than local GLBs; 78.85MJ compared to 12.67MJ per tonne of material. Two life cycle impact assessment methods were used, both of which showed that HCBs also have a higher embodied carbon footprint (excluding transportation), 86.6 kg compared to 3.42 kg of CO2 equivalents per tonne of material. These results reflect the fact that HCB production involves more materials and energy consumption. However, it was also established that globigerina limestone quarrying has a much larger impact on the use of land, resulting in more damage to the quality of ecosystems.