A regional supplementary cementitious material for the cement industry: Pistachio shell ash

The recycling of agricultural wastes in cementitious products has recently been a trendy approach for the sustainability goals of the world as it ensures economic and ecological advantages in addition to the safe disposal of these wastes. In this regard, the potentiality of a biomass ash obtained from the incineration of pistachio shell to serve as a supplementary cementitious material is documented in the present study. An increase of up to 30% in the amount of pistachio shell ash resulted in the proportional increase of both water requirement and setting time of the ordinary Portland cement by up to 54% and 300%, respectively. The incorporation of up to 20% pistachio shell ash into the cement yielded specimens of comparable or higher compressive strength values relatively varying between 98% and 117% at the 28 days and later curing ages. Beside the cementitious property, it was observed that a presence of graphitic structures in the pistachio shell ash remarkably improved the mechanical and the microstructural properties of cement mortars. In conclusion, at least 10% incorporation of this ash into the cement is highly recommended for the cement industry as it is beneficial in achieving the highest ultimate (400-day) compressive strength and promotes no loss on the early (2-day) compressive strength. [Display omitted] •The pistachio shell ash (PSA) was used as a supplementary cementitious material (SCM).•The presence of graphitic structures in PSA contributed to the early strength properties of cement.•10% PSA incorporation improved the compressive strength value of cement by 17% at 400 days.•The 28 days and the later age strength values were found to be satisfactory at even 20% PSA.•The use of PSA is strictly recommended for sustainability goals of the cement industry.