Date palm spikelet in mortar: Testing and modelling to reveal the mechanical performance

• Acceptable performance of modified mortars with moderate date palm spikelet content.
• Load transfer at interface is a key limiting factor for better mechanical performance.
• Finite element computation provides quantification of load transfer.
• Exact topography of spikelet is needed to proper evaluation of mechanical performance.
• Limited benefits of carbon nanotubes but prime role of spikelet chemical treatment.

Date palm residues capabilities in civil engineering are evaluated by combining numerical and experimental approaches. Date palm spikelet originated from Elghers variety is added to mortar as a raw material or after chemical modification. Evaluation of reinforcement effect is performed using mechanical testing. Finite element modelling is considered to predict the interfacial behaviour and mechanical performance under various structural and mechanical hypotheses. Experimental results show limited effect of untreated spikelet on mortar performance for volume reinforcement of 1%. Larger contents result in severe degradation of mechanical performance compared to reference mortar. The addition of carbon nanotubes improves slightly the performance. Chemical treatment using both NaOH and CaO results in reinforced effect of spikelet. Numerical predictions show limited load transfer across the matrix/untreated spikelet interface and large interface stiffness for those formulations including small spikelet, CNT and chemical treatment.