Environmental assessment of the use of ground olive stones in mortars. Reduction of CO2 emissions and production of sustainable mortars for buildings

Abstract

The current construction sector needs to include sustainability in the near future. The use of recycled aggregates (RA) instead of natural aggregates (NA) is proving to be an effective strategy to achieve more sustainable materials. In the case of Spain and within the agricultural sector, olive stones have great potential for use as RA, justified by several studies on their technical feasibility. This research evaluates environmentally through a Life Cycle Assessment (LCA) methodology the incorporation of ground olive stone (GOS) as a partial substitute for natural fine aggregate in 1m³ of mortar in different percentages. In a first phase, the environmental impacts are analysed with the scope of production of 1m³ of mortar (cradle to gate). Subsequently, a long-term assessment is carried out in the use phase to determine the environmental benefits of using the doped mortar in a façade for a new building. Among the most significant and innovative results, it is shown that for a doping percentage of 20 %, CO₂ emissions are reduced by 137.9 % for a simulation period of use of 35 years. This translates into preventing the net emission of 319.43 kg CO₂ eq/m³ of doped mortar into the atmosphere. In addition to avoiding the consumption of 3221.10 MJ/m³ of fossil fuels. All these results support the medium- and long-term environmental profitability of doping the mortar with GOS. Globally, it brings new environmental knowledge to the use of GOS as RAs over NAs and, jointly, to the sector's environmental sustainability objective.