Investigation of the mechanical and hygrothermal behavior of coffee ground wastes valorized as a building material: analysis of mix designs performance and sorption curve linearization effect

Coffee ground wastes (CGW) are by-products from the coffee-making processes. In this study, we propose to valorize them in construction materials at large scale. In particular, we investigate the mechanical and hygrothermal performances of earthen cob construction with incorporation of various amounts of CGW. Our results indicate that adding coffee grounds to cob enhances its hygrothermal performances as well as its compressive strength. An interesting enhancement of the lightened earth thermal characteristics as well as a good control of the hydric load in the air while maintaining acceptable mechanical properties is observed. Numerical analysis is used to evaluate the hygrothermal behavior of cob specimens to better understand their energy performances. A simplification of the simulation methods using a linearization of the sorption curve is incorporated to reduce calculation times and optimize outputs. The method is validated using experimental data, which shows a promising improvement compared to previous approaches. The proposed method can be faithfully applied to the study of hygrothermal behavior of biomaterials, which is strongly related to the building energy performance and the investigation of their durability in a fast and efficient way.

Automated summary

Coffee ground wastes (CGW) can be valorized in construction materials, particularly in earthen cob. Adding coffee grounds improves hygrothermal performances and compressive strength. Numerical analysis is used to evaluate the hygrothermal behavior of cob specimens, providing insight into energy performances.