Effects of cashew nutshell ash on the thermal and sustainability properties of cement concrete.

The present study valorizes cashew nutshell ash (CNA) and uses it at 5-20 wt. % of cement for concrete production. The concrete grades of 25-40 MPa were used as mix design proportions. The thermal and mechanical properties of the concrete samples were determined on day 28 of curing. Regression models were used to predict the thermophysical properties of the concrete specimens. Also, the concrete's sustainability was estimated via the inventory of carbon and energy (ICE). The results revealed that CNA enhanced the thermal insulating characteristics of the concrete produced. Maximum compressive strength was obtained at 15 wt. % of CNA content, while the developed models yielded high precision. Compared with the control concrete, the sustainability index decreased as CNA content in the mix increased, indicating that incorporating CNA in concrete production improves the sustainability of such concrete. Therefore, the outcome of this work can be beneficial, especially in hot or arid climate regions, and at the same time, achieve a cleaner environment.