Study of the combined effect of adding silica fume and red brick waste on the physico-mechanical properties of cement composites reinforced with treated Doum (Chamaeropshumilis) plant fibers

Abstract

The objective of this study is to examine the effect of using mineral additives from recyclable sources, such as silica fume and red brick waste, as partial substitutions for cement on the physico-mechanical properties of cement composites reinforced with plant fibers from the xerophytic Doum plant (Chamaeropshumilis). The aim is to develop bio-sourced, sustainable, and economically advantageous construction materials for potential applications in the construction and civil engineering industry.

The results have shown that the incorporation of these mineral additives led to an increase in the bulk density of the composites. The highest bulk density was achieved with an optimal ratio of 10% silica fume and 5% red brick waste by weight of cement, resulting in a 28% increase compared to the fibered control mortar. Additionally, these composites exhibited a reduction in water absorption, with a decrease of up to 47.5% compared to the fibered mortars without additives.

The values of ultrasonic pulse velocity (UPV) also increased with the incorporation of additives, indicating improved quality of the composites. Regarding compressive strength, a significant improvement was observed, with an optimal increase of 109% at 90 days for mixtures containing 10% silica fume and 5% red brick waste. However, a higher substitution rate resulted in a decrease in strength.

The composites also showed an increase in flexural strength, with improvements of up to 26% compared to the fibered control mortar. The best results were obtained with 10% silica fume and varying rates of red brick waste.

In conclusion, the incorporation of silica fume and red brick waste in cement-based composites led to improvements in properties such as bulk density, water absorption, ultrasonic pulse velocity, and mechanical strength, with optimal additive ratios.