Development of energy-saving innovative hydraulic mortars reusing spent coffee ground for applications in construction

abstract

This paper reports the development of green bio-composite mortars, obtained reusing spent coffee ground (SCG), an agri-food residue, in the light of the Circular Economy approach. This process can boost the sustainability in Construction and proposes an alternative to SCG disposal in landfill, potentially dangerous to humans and the environment. For the first time, specimens were produced and compared using different blends of conventional hydraulic binders (ordinary Portland cement and natural hydraulic lime); SCG partially substituted sand (up to 15 wt%, with a 2.5% increment) for the aggregate mix. The manufacturing process was performed at ambient conditions (20 degrees C, 65% RH) resulting highly sustainable, and consisted of simple operative steps reproducible in a real building site. The prepared mixes were fully characterised to assess their technological potentials in construction. Morphology analysis, performed by Scanning Electron Microscopy (SEM), showed SCG addition led to a more compact structure. Considering the functional properties, results widely range on binder blend base, offering various concrete applications; it was observed that with SCG addition, despite a decrease in the bulk density (up to 26%), the mechanical performance still remained suitable for proper masonry applications, ac-cording to the relevant standards (class of resistance M2.5-M10). A light water imbibition increase was registered (about 5%) while a significant decrease of the capillarity index was seen. Moreover, a robust thermal conduc-tivity reduction was observed (up to 72%), making the mortars highly suitable for energy-saving uses in building. Finally, a reduction in the manufacturing cost (up to 8%) was calculated, granting significant financial saving in light of the industrial symbiosis. These encouraging results showed that reusing SCG not only provides numerous benefits to the overall building performance and management but it is also a valid alternative to usual SCG disposal. The high amount of reused bio-waste significantly widens the knowledge of greener and more efficient building sector, making the prepared mortars promising candidates for the Minimum Environmental Criteria certification, in light of the recent EU regulations, and in line with the principles of the Circular Economy.

keywords

VALORISATION; VALORIZATION; WASTES; FOOD

subject category

Science & Technology - Other Topics; Engineering; Environmental Sciences & Ecology

authors

Saeli, M; Capela, MN; Piccirillo, C; Tobaldi, DM; Seabra, MP; Scalera, F; Striani, R; Corcione, CE; Campisi, T

Groups

G4 - Renewable Materials and Circular Economy

Projects

Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

M. Saeli would like to acknowledge the project PON "Research and Innovation 2014-2020" section 2 "AIM: Attraction and International Mobility" with D.D. 407 of February 27, 2018 co-financed by the European Social Fund - CUP B74I19000650001 - id project AIM 1890405-3, area: "Technologies for the Environments of Life", S.C. 08/C1, S.S.D. ICAR/10.M.N. Capela wishes to thank the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). D.M. Tobaldi would like to acknowledge the project EleGaNTe -PON ARS01_01007.Eng. G. Calandra, R. Errera, and A. Pace are thanked for assisting in specimens' production and testing.R.C. Pullar is thanked for helping with the English language editing.